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  • Understanding the concept of Inodes

    - by darkie15
    Hi All, I am referring to the link: http://www.tux4u.nl/freedocs/unix/draw/inode.pdf I am confused on parts: 1 12 direct block pointers 2 1 single indirect block pointer 3 1 double indirect block pointer 4 1 triple indirect block pointer Now the diagram says that each pointer is 32/64 bits. [Query]: Why and how are these values inferred? I mean why specifically have only 32 or 64 bit pointers? The diagram says, One data block{8 KB} for each pointer {4 bytes/8 bytes} [Query]: How does this actually work out? i.e. 8*1024 bytes / 8 bytes = 1024 bytes? What is the logic behind having a 8 bytes pointer for 8KB block? Regards, darkie.

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  • basename() returning int?

    - by EB
    Probably something stupid I'm missing but, why am I getting this warning? static void foo(char *path) { char *bname; char *path2 = strdup(path); bname = basename(path2); (line with basename() call): warning: assignment makes pointer from integer without a cast Indeed, if I change to this, the warning goes away: bname = (char *)basename(path2); man 3 basename tells me: char *basename(char *path); Both dirname() and basename() return pointers to null-terminated strings. What gives?

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  • C++: Overload != When == Overloaded

    - by Mark W
    Say I have a class where I overloaded the operator == as such: Class A { ... public: bool operator== (const A &rhs) const; ... }; ... bool A::operator== (const A &rhs) const { .. return isEqual; } I already have the operator == return the proper Boolean value. Now I want to extend this to the simple opposite (!=). I would like to call the overloaded == operator and return the opposite, i.e. something of the nature bool A::operator!= (const A &rhs) const { return !( this == A ); } Is this possible? I know this will not work, but it exemplifies what I would like to have. I would like to keep only one parameter for the call: rhs. Any help would be appreciated, because I could not come up with an answer after several search attempts.

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  • Normalising book titles - Python

    - by RadiantHex
    Hi folks, I have a list of books titles: "The Hobbit: 70th Anniversary Edition" "The Hobbit" "The Hobbit (Illustrated/Collector Edition)[There and Back Again]" "The Hobbit: or, There and Back Again" "The Hobbit: Gift Pack" and so on... I thought that if I normalised the titles somehow, it would be easier to implement an automated way to know what book each edition is referring to. normalised = ''.join([char for char in title if char in (string.ascii_letters + string.digits)]) or normalised = '' for char in title: if char in ':/()|': break normalised += char return normalised But obviously they are not working as intended, as titles can contain special characters and editions can basically have very different title layouts. Help would be very much appreciated! Thanks :)

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  • Can I use a static var to "cache" the result? C++

    - by flyout
    I am using a function that returns a char*, and right now I am getting the compiler warning "returning address of local variable or temporary", so I guess I will have to use a static var for the return, my question is can I make something like if(var already set) return var else do function and return var? This is my function: char * GetUID() { TCHAR buf[20]; StringCchPrintf(buf, 20*sizeof(char), TEXT("%s"), someFunction()); return buf; } And this is what I want to do: char * GetUID() { static TCHAR buf[20]; if(strlen(buf)!=0) return buf; StringCchPrintf(buf, 20*sizeof(char), TEXT("%s"), someFunction()); return buf; } Is this a well use of static vars? And should I use ZeroMemory(&buf, 20*sizeof(char))? I removed it because if I use it above the if(strlen...) my TCHAR length is never 0, should I use it below?

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  • Passing a column name instead of index in sqlite3

    - by user271753
    The problem code: NSString *query = @"SELECT Name FROM Category"; sqlite3_stmt *statement; if (sqlite3_prepare_v2(database, [query UTF8String], -1, &statement, nil) == SQLITE_OK) { while (sqlite3_step(statement) == SQLITE_ROW) { char *row =(char *)sqlite3_column_text(statement,0); char *rowData = (char *)sqlite3_column_text(statement,1); NSString *fieldName = [[NSString alloc] initWithUTF8String:row]; NSString *fieldValue = [[NSString alloc] initWithUTF8String:rowData]; NSLog(@"%@",fieldName); NSLog(@"%@",fieldValue); [fieldName release]; [fieldValue release]; } sqlite3_finalize(statement); } char *row =(char *)sqlite3_column_text(statement,0); In the above code instead of 0 can't I just pass a column name? How can I do that ?

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  • using structures with multidimentional tables

    - by gem
    I have a table of structures and this structures are 2 dimentional table of constants. can you teach me on how to get the values in the table of constants. (note following is just example) typedef struct { unsigned char ** Type1; unsigned char ** Type2; } Formula; typedef struct { Formula tformula[size]; } table; const table Values = { (unsigned char**) &(default_val1), (unsigned char**) &(default_val2) }; const unsigned char default_val1[4][4] = { {0,1,2,3}, {4,5,6,7}, {8,9,0,11}, {12,13,14,15} } const unsigned char default_val2[4][4] = { {15,16,17,13}, {14,15,16,17}, {18,19,10,21}, {22,23,24,25} }

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  • C++ - Error: expected unqualified-id before ‘using’

    - by Francisco P.
    Hello, everyone. I am having some trouble on a project I'm working on. Here's the header file for the calor class: #ifndef _CALOR_ #define _CALOR_ #include "gradiente.h" using namespace std; class Calor : public Gradiente { public: Calor(); Calor(int a); ~Calor(); int getTemp(); int getMinTemp(); void setTemp(int a); void setMinTemp(int a); void mostraSensor(); }; #endif When I try to compile it: calor.h|6|error: expected unqualified-id before ‘using’| Why does this happen? I've been searching online and learned this error occurs mostly due to corrupted included files. Makes no sense to me, though. This class inherits from gradiente: #ifndef _GRADIENTE_ #define _GRADIENTE_ #include "sensor.h" using namespace std; class Gradiente : public Sensor { protected: int vActual, vMin; public: Gradiente(); ~Gradiente(); } #endif Which in turn inherits from sensor #ifndef _SENSOR_ #define _SENSOR_ #include <iostream> #include <fstream> #include <string> #include "definicoes.h" using namespace std; class Sensor { protected: int tipo; int IDsensor; bool estadoAlerta; bool estadoActivo; static int numSensores; public: Sensor(/*PARAMETROS*/); Sensor(ifstream &); ~Sensor(); int getIDsensor(); bool getEstadoAlerta(); bool getEstadoActivo(); void setEstadoAlerta(int a); void setEstadoActivo(int a); virtual void guardaSensor(ofstream &); virtual void mostraSensor(); // FUNÇÃO COMUM /* virtual int funcaoComum() = 0; virtual int funcaoComum(){return 0;};*/ }; #endif For completeness' sake, here's definicoes.h #ifndef _DEFINICOES_ #define _DEFINICOES_ const unsigned int SENSOR_MOVIMENTO = 0; const unsigned int SENSOR_SOM = 1; const unsigned int SENSOR_PRESSAO = 2; const unsigned int SENSOR_CALOR = 3; const unsigned int SENSOR_CONTACTO = 4; const unsigned int MIN_MOVIMENTO = 10; const unsigned int MIN_SOM = 10; const unsigned int MIN_PRESSAO = 10; const unsigned int MIN_CALOR = 35; #endif Any help'd be much appreciated. Thank you for your time. Thanks for your time!

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  • How do I get a array to just count how many numbers there are instead of counting the value of each number?

    - by Chad Loos
    //This is the output of the program *** start of 276 2D Arrays_03.cpp program *** Number Count Total 1 3 3 2 6 9 3 15 24 4 6 30 5 9 39 *** end of 276 2D Arrays_03.cpp program *** #include <iostream> #include <string> #include <iomanip> using namespace std; const int COLUMN_SIZE = 13; int main(void) { const int ROW_SIZE = 3; const int COUNT_SIZE = 5; void countValues(const int[][COLUMN_SIZE], const int, int[]); void display(const int [], const int); int numbers[ROW_SIZE][COLUMN_SIZE] = {{1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3, 2}, {2, 1, 3, 4, 5, 3, 2, 3, 5, 3, 4, 5, 3}, {3, 4, 5, 3, 2, 1, 3, 4, 5, 3, 2, 3, 5}}; int counts[COUNT_SIZE] = {0}; string choice; cout << "*** start of 276 2D Arrays_03.cpp program ***" << endl; cout << endl; countValues(numbers, ROW_SIZE, counts); display(counts, COUNT_SIZE); cout << endl; cout << endl; cout << "*** end of 276 2D Arrays_03.cpp program ***" << endl << endl; cin.get(); return 0; } // end main() This is the function where I need to count each of the values. I know how to sum rows and cols, but I'm not quite sure of the code to just tally the values themselves. void countValues(const int numbers[][COLUMN_SIZE], const int ROW_SIZE, int counts[]) This is what I have so far. { for (int index = 0; index < ROW_SIZE; index++) counts[index]; {

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  • C++ Static Array Initialization - Memory Issue

    - by donalmg
    Hi, I have a header file which contains a member variable declaration of a static char array: class ABC { public: static char newArray[4]; // other variables / functions private: void setArray(int i, char * ptr); } In the CPP file, I have the array initialized to NULL: char ABC::newArray[4] = {0}; In the ABC constructor, I need to overwrite this value with a value constructed at runtime, such as the encoding of an integer: ABC::ABC() { int i; //some int value defined at runtime memset(newArray, 0, 4); // not sure if this is necessary setArray(i,newArray); } ... void setArray(int i, char * value) { // encoding i to set value[0] ... value [3] } When I return from this function, and print the modified newArray value, it prints out many more characters than the 4 specified in the array declaration. Any ideas why this is the case. I just want to set the char array to 4 characters and nothing further. Thanks...

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  • Obtaining a timestamp every minute from a database

    - by soumen
    This is my table structure: +------------+-----------+------+-----+---------+-------+ | Field | Type | Null | Key | Default | Extra | +------------+-----------+------+-----+---------+-------+ | uid | char(255) | NO | MUL | NULL | | | cid | char(255) | NO | MUL | NULL | | | ip_address | char(15) | NO | | NULL | | | user_agent | char(255) | YES | | NULL | | | open_date | datetime | NO | MUL | NULL | | | referrer | char(255) | YES | | NULL | | | environ | text | YES | | NULL | | | country | char(255) | NO | MUL | NULL | | +------------+-----------+------+-----+---------+-------+ I want to get a timestamp every minute within a range. select DATE_ADD(open_date,interval 1 minute) as m from open_track.camp_open where open_date between "2009-05-13 00:00:00" and "2009-05-13 23:59:59" limit 10; outputs +---------------------+ | m | +---------------------+ | 2009-05-13 00:01:01 | | 2009-05-13 00:01:02 | | 2009-05-13 00:01:03 | | 2009-05-13 00:01:03 | | 2009-05-13 00:01:04 | | 2009-05-13 00:01:05 | | 2009-05-13 00:01:06 | | 2009-05-13 00:01:08 | | 2009-05-13 00:01:08 | | 2009-05-13 00:01:09 | +---------------------+ Please advise me.

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  • can't compile min_element in c++

    - by Vincenzo
    This is my code: #include <algorithm> #include <vector> #include <string> using namespace std; class A { struct CompareMe { bool operator() (const string*& s1, const string*& s2) const { return true; } }; void f() { CompareMe comp; vector<string*> v; min_element(v.begin(), v.end(), comp); } }; And this is the error: error: no match for call to ‘(A::CompareMe) (std::string*&, std::string*&)’ test.cpp:7: note: candidates are: bool A::CompareMe::operator()(const std::string*&, const std::string*&) const I feel that there is some syntax defect, but can't find out which one. Please, help!

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  • Structs and pointers

    - by user1763861
    I have a few questions about structs and pointers For this struct: typedef struct tNode_t { char *w; } tNode; How come if I want to change/know the value of *w I need to use t.w = "asdfsd" instead of t->w = "asdfasd"? And I compiled this successfully without having t.w = (char *) malloc(28*sizeof(char)); in my testing code, is there a reason why tt's not needed? Sample main: int main() { tNode t; char w[] = "abcd"; //t.word = (char *) malloc(28*sizeof(char)); t.word = w; printf("%s", t.word); } Thanks.

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  • Need some help on how to replay the last game of a java maze game

    - by Marty
    Hello, I am working on creating a Java maze game for a project. The maze is displayed on the console as standard output not in an applet. I have created most of hte code I need, however I am stuck at one problem and that is I need a user to be able to replay the last game i.e redraw the maze with the users moves but without any input from the user. I am not sure on what course of action to take, i was thinking about copying each users move or the position of each move into another array, as you can see i have 2 variables which hold the position of the player, plyrX and plyrY do you think copying these values into a new array after each move would solve my problem and how would i go about this? I have updated my code, apologies about the textIO.java class not being present, not sure how to resolve that exept post a link to TextIO.java [TextIO.java][1] My code below is updated with a new array of type char to hold values from the original maze (read in from text file and displayed using unicode characters) and also to new variables c_plyrX and c_plyrY which I am thinking should hold the values of plyrX and plyrY and copy them into the new array. When I try to call the replayGame(); method from the menu the maze loads for a second then the console exits so im not sure what I am doing wrong Thanks public class MazeGame { //unicode characters that will define the maze walls, //pathways, and in game characters. final static char WALL = '\u2588'; //wall final static char PATH = '\u2591'; //pathway final static char PLAYER = '\u25EF'; //player final static char ENTRANCE = 'E'; //entrance final static char EXIT = '\u2716'; //exit //declaring member variables which will hold the maze co-ordinates //X = rows, Y = columns static int entX = 0; //entrance X co-ordinate static int entY = 1; //entrance y co-ordinate static int plyrX = 0; static int plyrY = 1; static int exitX = 24; //exit X co-ordinate static int exitY = 37; //exit Y co-ordinate //static member variables which hold maze values //used so values can be accessed from different methods static int rows; //rows variable static int cols; //columns variable static char[][] maze; //defines 2 dimensional array to hold the maze //variables that hold player movement values static char dir; //direction static int spaces; //amount of spaces user can travel //variable to hold amount of moves the user has taken; static int movesTaken = 0; //new array to hold player moves for replaying game static char[][] mazeCopy; static int c_plyrX; static int c_plyrY; /** userMenu method for displaying the user menu which will provide various options for * the user to choose such as play a maze game, get instructions, etc. */ public static void userMenu(){ TextIO.putln("Maze Game"); TextIO.putln("*********"); TextIO.putln("Choose an option."); TextIO.putln(""); TextIO.putln("1. Play the Maze Game."); TextIO.putln("2. View Instructions."); TextIO.putln("3. Replay the last game."); TextIO.putln("4. Exit the Maze Game."); TextIO.putln(""); int option; //variable for holding users option TextIO.put("Type your choice: "); option = TextIO.getlnInt(); //gets users option //switch statement for processing menu options switch(option){ case 1: playMazeGame(); case 2: instructions(); case 3: if (c_plyrX == plyrX && c_plyrY == plyrY)replayGame(); else { TextIO.putln("Option not available yet, you need to play a game first."); TextIO.putln(); userMenu(); } case 4: System.exit(0); //exits the user out of the console default: TextIO.put("Option must be 1, 2, 3 or 4"); } } //end of userMenu /**main method, will call the userMenu and get the users choice and call * the relevant method to execute the users choice. */ public static void main(String[]args){ userMenu(); //calls the userMenu method } //end of main method /**instructions method, displays instructions on how to play * the game to the user/ */ public static void instructions(){ TextIO.putln("To beat the Maze Game you have to move your character"); TextIO.putln("through the maze and reach the exit in as few moves as possible."); TextIO.putln(""); TextIO.putln("Your characer is displayed as a " + PLAYER); TextIO.putln("The maze exit is displayed as a " + EXIT); TextIO.putln("Reach the exit and you have won escaped the maze."); TextIO.putln("To control your character type the direction you want to go"); TextIO.putln("and how many spaces you want to move"); TextIO.putln("for example 'D3' will move your character"); TextIO.putln("down 3 spaces."); TextIO.putln("Remember you can't walk through walls!"); boolean insOption; //boolean variable TextIO.putln(""); TextIO.put("Do you want to play the Maze Game now? (Y or N) "); insOption = TextIO.getlnBoolean(); if (insOption == true)playMazeGame(); else userMenu(); } //end of instructions method /**playMazeGame method, calls the loadMaze method and the charMove method * to start playing the Maze Game. */ public static void playMazeGame(){ loadMaze(); plyrMoves(); } //end of playMazeGame method /**loadMaze method, loads the 39x25 maze from the MazeGame.txt text file * and inserts values from the text file into the maze array and * displays the maze on screen using the unicode block characters. * plyrX and plyrY variables are set at their staring co ordinates so that when * a game is completed and the user selects to play a new game * the player character will always be at position 01. */ public static void loadMaze(){ plyrX = 0; plyrY = 1; TextIO.readFile("MazeGame.txt"); //now reads from the external MazeGame.txt file rows = TextIO.getInt(); //gets the number of rows from text file to create X dimensions cols = TextIO.getlnInt(); //gets number of columns from text file to create Y dimensions maze = new char[rows][cols]; //creates maze array of base type char with specified dimnensions //loop to process the array and read in values from the text file. for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ maze[i][j] = TextIO.getChar(); } TextIO.getln(); } //end for loop TextIO.readStandardInput(); //closes MazeGame.txt file and reads from //standard input. //loop to process the array values and display as unicode characters for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ if (i == plyrX && j == plyrY){ plyrX = i; plyrY = j; TextIO.put(PLAYER); //puts the player character at player co-ords } else{ if (maze[i][j] == '0') TextIO.putf("%c",WALL); //puts wall block if (maze[i][j] == '1') TextIO.putf("%c",PATH); //puts path block if (maze[i][j] == '2') { entX = i; entY = j; TextIO.putf("%c",ENTRANCE); //puts entrance character } if (maze[i][j] == '3') { exitX = i; //holds value of exit exitY = j; //co-ordinates TextIO.putf("%c",EXIT); //puts exit character } } } TextIO.putln(); } //end for loop } //end of loadMaze method /**redrawMaze method, method for redrawing the maze after each move. * */ public static void redrawMaze(){ TextIO.readFile("MazeGame.txt"); //now reads from the external MazeGame.txt file rows = TextIO.getInt(); //gets the number of rows from text file to create X dimensions cols = TextIO.getlnInt(); //gets number of columns from text file to create Y dimensions maze = new char[rows][cols]; //creates maze array of base type char with specified dimnensions //loop to process the array and read in values from the text file. for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ maze[i][j] = TextIO.getChar(); } TextIO.getln(); } //end for loop TextIO.readStandardInput(); //closes MazeGame.txt file and reads from //standard input. //loop to process the array values and display as unicode characters for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ if (i == plyrX && j == plyrY){ plyrX = i; plyrY = j; TextIO.put(PLAYER); //puts the player character at player co-ords } else{ if (maze[i][j] == '0') TextIO.putf("%c",WALL); //puts wall block if (maze[i][j] == '1') TextIO.putf("%c",PATH); //puts path block if (maze[i][j] == '2') { entX = i; entY = j; TextIO.putf("%c",ENTRANCE); //puts entrance character } if (maze[i][j] == '3') { exitX = i; //holds value of exit exitY = j; //co-ordinates TextIO.putf("%c",EXIT); //puts exit character } } } TextIO.putln(); } //end for loop } //end redrawMaze method /**replay game method * */ public static void replayGame(){ c_plyrX = plyrX; c_plyrY = plyrY; TextIO.readFile("MazeGame.txt"); //now reads from the external MazeGame.txt file rows = TextIO.getInt(); //gets the number of rows from text file to create X dimensions cols = TextIO.getlnInt(); //gets number of columns from text file to create Y dimensions mazeCopy = new char[rows][cols]; //creates maze array of base type char with specified dimnensions //loop to process the array and read in values from the text file. for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ mazeCopy[i][j] = TextIO.getChar(); } TextIO.getln(); } //end for loop TextIO.readStandardInput(); //closes MazeGame.txt file and reads from //standard input. //loop to process the array values and display as unicode characters for (int i = 0; i<rows; i++){ for (int j = 0; j<cols; j++){ if (i == c_plyrX && j == c_plyrY){ c_plyrX = i; c_plyrY = j; TextIO.put(PLAYER); //puts the player character at player co-ords } else{ if (mazeCopy[i][j] == '0') TextIO.putf("%c",WALL); //puts wall block if (mazeCopy[i][j] == '1') TextIO.putf("%c",PATH); //puts path block if (mazeCopy[i][j] == '2') { entX = i; entY = j; TextIO.putf("%c",ENTRANCE); //puts entrance character } if (mazeCopy[i][j] == '3') { exitX = i; //holds value of exit exitY = j; //co-ordinates TextIO.putf("%c",EXIT); //puts exit character } } } TextIO.putln(); } //end for loop } //end replayGame method /**plyrMoves method, method for moving the players character * around the maze. */ public static void plyrMoves(){ int nplyrX = plyrX; int nplyrY = plyrY; int pMoves; direction(); //UP if (dir == 'U' || dir == 'u'){ nplyrX = plyrX; nplyrY = plyrY; for(pMoves = 0; pMoves <= spaces; pMoves++){ if (maze[nplyrX][nplyrY] == '0'){ TextIO.putln("Invalid move, try again."); } else if (pMoves != spaces){ nplyrX =plyrX + 1; } else { plyrX = plyrX-spaces; c_plyrX = plyrX; movesTaken++; } } }//end UP if //DOWN if (dir == 'D' || dir == 'd'){ nplyrX = plyrX; nplyrY = plyrY; for (pMoves = 0; pMoves <= spaces; pMoves ++){ if (maze[nplyrX][nplyrY] == '0'){ TextIO.putln("Invalid move, try again"); } else if (pMoves != spaces){ nplyrX = plyrX+1; } else{ plyrX = plyrX+spaces; c_plyrX = plyrX; movesTaken++; } } } //end DOWN if //LEFT if (dir == 'L' || dir =='l'){ nplyrX = plyrX; nplyrY = plyrY; for (pMoves = 0; pMoves <= spaces; pMoves++){ if (maze[nplyrX][nplyrY] == '0'){ TextIO.putln("Invalid move, try again"); } else if (pMoves != spaces){ nplyrY = plyrY + 1; } else{ plyrY = plyrY-spaces; c_plyrY = plyrY; movesTaken++; } } } //end LEFT if //RIGHT if (dir == 'R' || dir == 'r'){ nplyrX = plyrX; nplyrY = plyrY; for (pMoves = 0; pMoves <= spaces; pMoves++){ if (maze[nplyrX][nplyrY] == '0'){ TextIO.putln("Invalid move, try again."); } else if (pMoves != spaces){ nplyrY += 1; } else{ plyrY = plyrY+spaces; c_plyrY = plyrY; movesTaken++; } } } //end RIGHT if //prints message if player escapes from the maze. if (maze[plyrX][plyrY] == '3'){ TextIO.putln("****Congratulations****"); TextIO.putln(); TextIO.putln("You have escaped from the maze."); TextIO.putln(); userMenu(); } else{ movesTaken++; redrawMaze(); plyrMoves(); } } //end of plyrMoves method /**direction, method * */ public static char direction(){ TextIO.putln("Enter the direction you wish to move in and the distance"); TextIO.putln("i.e D3 = move down 3 spaces"); TextIO.putln("U - Up, D - Down, L - Left, R - Right: "); dir = TextIO.getChar(); if (dir =='U' || dir == 'D' || dir == 'L' || dir == 'R' || dir == 'u' || dir == 'd' || dir == 'l' || dir == 'r'){ spacesMoved(); } else{ loadMaze(); TextIO.putln("Invalid direction!"); TextIO.put("Direction must be one of U, D, L or R"); direction(); } return dir; //returns the value of dir (direction) } //end direction method /**spaces method, gets the amount of spaces the user wants to move * */ public static int spacesMoved(){ TextIO.putln(" "); spaces = TextIO.getlnInt(); if (spaces <= 0){ loadMaze(); TextIO.put("Invalid amount of spaces, try again"); spacesMoved(); } return spaces; } //end spacesMoved method } //end of MazeGame class

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  • Binary Search Tree Implementation

    - by Gabe
    I've searched the forum, and tried to implement the code in the threads I found. But I've been working on this real simple program since about 10am, and can't solve the seg. faults for the life of me. Any ideas on what I'm doing wrong would be greatly appreciated. BST.h (All the implementation problems should be in here.) #ifndef BST_H_ #define BST_H_ #include <stdexcept> #include <iostream> #include "btnode.h" using namespace std; /* A class to represent a templated binary search tree. */ template <typename T> class BST { private: //pointer to the root node in the tree BTNode<T>* root; public: //default constructor to make an empty tree BST(); /* You have to document these 4 functions */ void insert(T value); bool search(const T& value) const; bool search(BTNode<T>* node, const T& value) const; void printInOrder() const; void remove(const T& value); //function to print out a visual representation //of the tree (not just print the tree's values //on a single line) void print() const; private: //recursive helper function for "print()" void print(BTNode<T>* node,int depth) const; }; /* Default constructor to make an empty tree */ template <typename T> BST<T>::BST() { root = NULL; } template <typename T> void BST<T>::insert(T value) { BTNode<T>* newNode = new BTNode<T>(value); cout << newNode->data; if(root == NULL) { root = newNode; return; } BTNode<T>* current = new BTNode<T>(NULL); current = root; current->data = root->data; while(true) { if(current->left == NULL && current->right == NULL) break; if(current->right != NULL && current->left != NULL) { if(newNode->data > current->data) current = current->right; else if(newNode->data < current->data) current = current->left; } else if(current->right != NULL && current->left == NULL) { if(newNode->data < current->data) break; else if(newNode->data > current->data) current = current->right; } else if(current->right == NULL && current->left != NULL) { if(newNode->data > current->data) break; else if(newNode->data < current->data) current = current->left; } } if(current->data > newNode->data) current->left = newNode; else current->right = newNode; return; } //public helper function template <typename T> bool BST<T>::search(const T& value) const { return(search(root,value)); //start at the root } //recursive function template <typename T> bool BST<T>::search(BTNode<T>* node, const T& value) const { if(node == NULL || node->data == value) return(node != NULL); //found or couldn't find value else if(value < node->data) return search(node->left,value); //search left subtree else return search(node->right,value); //search right subtree } template <typename T> void BST<T>::printInOrder() const { //print out the value's in the tree in order // //You may need to use this function as a helper //and create a second recursive function //(see "print()" for an example) } template <typename T> void BST<T>::remove(const T& value) { if(root == NULL) { cout << "Tree is empty. No removal. "<<endl; return; } if(!search(value)) { cout << "Value is not in the tree. No removal." << endl; return; } BTNode<T>* current; BTNode<T>* parent; current = root; parent->left = NULL; parent->right = NULL; cout << root->left << "LEFT " << root->right << "RIGHT " << endl; cout << root->data << " ROOT" << endl; cout << current->data << "CURRENT BEFORE" << endl; while(current != NULL) { cout << "INTkhkjhbljkhblkjhlk " << endl; if(current->data == value) break; else if(value > current->data) { parent = current; current = current->right; } else { parent = current; current = current->left; } } cout << current->data << "CURRENT AFTER" << endl; // 3 cases : //We're looking at a leaf node if(current->left == NULL && current->right == NULL) // It's a leaf { if(parent->left == current) parent->left = NULL; else parent->right = NULL; delete current; cout << "The value " << value << " was removed." << endl; return; } // Node with single child if((current->left == NULL && current->right != NULL) || (current->left != NULL && current->right == NULL)) { if(current->left == NULL && current->right != NULL) { if(parent->left == current) { parent->left = current->right; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->right; cout << "The value " << value << " was removed." << endl; delete current; } } else // left child present, no right child { if(parent->left == current) { parent->left = current->left; cout << "The value " << value << " was removed." << endl; delete current; } else { parent->right = current->left; cout << "The value " << value << " was removed." << endl; delete current; } } return; } //Node with 2 children - Replace node with smallest value in right subtree. if (current->left != NULL && current->right != NULL) { BTNode<T>* check; check = current->right; if((check->left == NULL) && (check->right == NULL)) { current = check; delete check; current->right = NULL; cout << "The value " << value << " was removed." << endl; } else // right child has children { //if the node's right child has a left child; Move all the way down left to locate smallest element if((current->right)->left != NULL) { BTNode<T>* leftCurrent; BTNode<T>* leftParent; leftParent = current->right; leftCurrent = (current->right)->left; while(leftCurrent->left != NULL) { leftParent = leftCurrent; leftCurrent = leftCurrent->left; } current->data = leftCurrent->data; delete leftCurrent; leftParent->left = NULL; cout << "The value " << value << " was removed." << endl; } else { BTNode<T>* temp; temp = current->right; current->data = temp->data; current->right = temp->right; delete temp; cout << "The value " << value << " was removed." << endl; } } return; } } /* Print out the values in the tree and their relationships visually. Sample output: 22 18 15 10 9 5 3 1 */ template <typename T> void BST<T>::print() const { print(root,0); } template <typename T> void BST<T>::print(BTNode<T>* node,int depth) const { if(node == NULL) { std::cout << std::endl; return; } print(node->right,depth+1); for(int i=0; i < depth; i++) { std::cout << "\t"; } std::cout << node->data << std::endl; print(node->left,depth+1); } #endif main.cpp #include "bst.h" #include <iostream> using namespace std; int main() { BST<int> tree; cout << endl << "LAB #13 - BINARY SEARCH TREE PROGRAM" << endl; cout << "----------------------------------------------------------" << endl; // Insert. cout << endl << "INSERT TESTS" << endl; // No duplicates allowed. tree.insert(0); tree.insert(5); tree.insert(15); tree.insert(25); tree.insert(20); // Search. cout << endl << "SEARCH TESTS" << endl; int x = 0; int y = 1; if(tree.search(x)) cout << "The value " << x << " is on the tree." << endl; else cout << "The value " << x << " is NOT on the tree." << endl; if(tree.search(y)) cout << "The value " << y << " is on the tree." << endl; else cout << "The value " << y << " is NOT on the tree." << endl; // Removal. cout << endl << "REMOVAL TESTS" << endl; tree.remove(0); tree.remove(1); tree.remove(20); // Print. cout << endl << "PRINTED DIAGRAM OF BINARY SEARCH TREE" << endl; cout << "----------------------------------------------------------" << endl; tree.print(); cout << endl << "Program terminated. Goodbye." << endl << endl; } BTNode.h #ifndef BTNODE_H_ #define BTNODE_H_ #include <iostream> /* A class to represent a node in a binary search tree. */ template <typename T> class BTNode { public: //constructor BTNode(T d); //the node's data value T data; //pointer to the node's left child BTNode<T>* left; //pointer to the node's right child BTNode<T>* right; }; /* Simple constructor. Sets the data value of the BTNode to "d" and defaults its left and right child pointers to NULL. */ template <typename T> BTNode<T>::BTNode(T d) : left(NULL), right(NULL) { data = d; } #endif Thanks.

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  • Im getting fatal errors... can anyone help me edit my program!

    - by user350217
    The errors i am getting are: Error 1 error LNK2019: unresolved external symbol "double __cdecl getDollarAmt(void)" (? getDollarAmt@@YANXZ) referenced in function _main hid.obj Error 2 fatal error LNK1120: 1 unresolved externals this is my program: #include<iostream> #include<cmath> #include<string> using namespace std; double getDollarAmt(); void displayCurrencies(); char getCurrencySelection (float amtExchanged); bool isSelectionValid(char selection); double calcExchangeAmt (float amtExchanged, char selection); void displayResults(double newAmount, float amtExchanged, char selection, char yesNo); const double russianRubles = 31.168; const double northKoreanWon = .385; const double chineseYuan = 6.832; const double canadianDollar = 1.1137; const double cubanPeso = 1.0; const double ethiopianBirr = 9.09; const double egyptianPound = 5.6275; const double tunisianDinar = 1.3585; const double thaiBaht = 34.4; /****** I changed the variables to global variables so you don't have to worry about accidentally setting them to 0 or assigning over a value that you need ********/ float amtEchanged = 0.0; char selection; char yesNo; double newAmount; int main() { float amtExchanged = 0.0; selection = 'a'; yesNo = 'y'; newAmount = 0.0; getDollarAmt (); displayCurrencies(); getCurrencySelection (amtExchanged); isSelectionValid(selection);/**** you only need to use the selection variable ****/ calcExchangeAmt (amtExchanged, selection); displayResults(newAmount, amtExchanged, selection, yesNo); return 0; } double getDollarAmt (float amtExchanged) // promt user for eachange amount and return it to main { float amtExchanged0;//created temporary variable to set amtExchanged to cout<< "Please enter the total dollar amount to exchange: "; cin>> amtExchanged0; amtExchanged = amtExchanged0;//setting amtExchanged to the right value return amtExchanged; } void displayCurrencies() // display list of currencies { cout<<"A Russian Ruble"<<endl <<"B North Korean Won"<<endl <<"C Chinese Yuan"<<endl <<"D Cuban Peso"<<endl <<"E Ethiopian Birr"<<endl <<"F Thai Baht"<<endl <<"G Canadian Dollars"<<endl <<"H Tunisian Dinar"<<endl <<"I Egyptian Pound"<<endl; } char getCurrencySelection (float amtExchanged) // make a selection and return to main { char selection0;//again, created a temporary variable for selection cout<<"Please enter your selection: "; cin>>selection0; selection = selection0;//setting the temporary variable to the actual variable you use /***** we are now going to see if isSelectionValid returns false. if it returns false, that means that their selection was not character A-H. if it is false we keep calling getCurrencySelection *****/ if(isSelectionValid(selection)==false) { cout<<"Sorry, the selection you chose is invalid."<<endl; getCurrencySelection(amtExchanged); } return selection; } bool isSelectionValid(char selection) // this fuction is supposed to be called from getCurrencySelection, the selction // must be sent to isSelectionValid to determine if its valid // if selection is valid send it bac to getCurrencySelection // if it is false then it is returned to getCurrencySelection and prompted to // make another selection until the selection is valid, then it is returned to main. { /**** i'm not sure if this is what you mean, all i am doing is making sure that their selection is A-H *****/ if(selection=='A' || selection=='B' || selection=='C' || selection=='D' || selection=='E' || selection=='F' || selection=='G' || selection=='H' || selection=='I') return true; else return false; } double calcExchangeAmt (float amtExchanged,char selection) // function calculates the amount of money to be exchanged { switch (toupper(selection)) { case 'A': newAmount =(russianRubles) * (amtExchanged); break; case 'B': newAmount = (northKoreanWon) * (amtExchanged); break; case 'C': newAmount = (chineseYuan) * (amtExchanged); break; case 'D': newAmount = (canadianDollar) * (amtExchanged); break; case 'E': newAmount = (cubanPeso) * (amtExchanged); break; case 'F': newAmount = (ethiopianBirr) * (amtExchanged); break; case 'G': newAmount = (egyptianPound) * (amtExchanged); break; case 'H': newAmount = (tunisianDinar) * (amtExchanged); break; case 'I': newAmount = (thaiBaht) * (amtExchanged); break; } return newAmount; } void displayResults(double newAmount, float amtExchanged, char selection, char yesNo) // displays results and asked to repeat. IF they want to repeat it clears the screen and starts over. { switch(toupper(selection)) { case 'A': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Russian Rubles."<<endl<<endl; break; case 'B': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" North Korean Won."<<endl<<endl; break; case 'C': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Chinese Yuan."<<endl<<endl; break; case 'D': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Cuban Pesos."<<endl<<endl; break; case 'E': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Ethiopian Birr."<<endl<<endl; break; case 'F': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Thai Baht."<<endl<<endl; break; case 'G': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Canadian Dollars."<<endl<<endl; break; case 'H': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Tunisian Dinar."<<endl<<endl; break; case 'I': cout<<"$"<<amtExchanged<<" is "<<newAmount<<" Egyptian Pound."<<endl<<endl; break; } cout<<"Do you wish to continue? (Y for Yes / N for No)"; cin>>yesNo; if(yesNo=='y' || yesNo=='Y') { getDollarAmt(); } else { system("cls"); } }

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  • Setting an XAML Window always on top (but no TopMost property)

    - by Brian Scherady
    I am developing an application based on OptiTrack SDK (from NaturalPoint). I need to run the application window as "Always on Top". The window is designed in XAML and is controled in the class "CameraView" but it does not seem to include a "TopMost" property or equivalent. Attached are the code of "CameraView.xaml.cs" and the code of "CameraView.xaml" that are part of OptiTrack SDK (NaturalPoint) called "Single_Camera_CSharp_.NET_3.0". One could expect the class CameraView to contain properties or members to set the position of the window on the screen or to set it to TopMost but as far as searched I found nothing. I wonder what I should do. Thank you, Brian ================ "CameraView.xaml.cs" using System; using System.IO; using System.Net; using System.Windows; using System.Windows.Controls; using System.Windows.Data; using System.Windows.Media; using System.Windows.Media.Animation; using System.Windows.Navigation; using System.Drawing.Imaging; using System.Drawing.Drawing2D; using System.Windows.Threading; namespace TestProject { public partial class CameraView { private const int NP_OPTION_OBJECT_COLOR_OPTION = 3; private const int NP_OPTION_VIDEO_TYPE = 48; private const int NP_OPTION_NUMERIC_DISPLAY_ON = 71; private const int NP_OPTION_NUMERIC_DISPLAY_OFF = 72; private const int NP_OPTION_FETCH_RLE = 73; private const int NP_OPTION_FETCH_GRAYSCALE = 74; private const int NP_OPTION_FRAME_DECIMATION = 52; private const int NP_OPTION_INTENSITY = 50; private const int NP_OPTION_SEND_EMPTY_FRAMES = 41; private const int NP_OPTION_THRESHOLD = 5; private const int NP_OPTION_EXPOSURE = 46; private const int NP_OPTION_SEND_FRAME_MASK = 73; private const int NP_OPTION_TEXT_OVERLAY_OPTION = 74; // public delegate void OnCameraViewCreate(CameraView camera); // public static OnCameraViewCreate onCameraViewCreate; private System.Drawing.Bitmap raw = new System.Drawing.Bitmap(353, 288, System.Drawing.Imaging.PixelFormat.Format32bppArgb); private int mFrameCounter; private int mDisplayCounter; private DispatcherTimer timer1 = new DispatcherTimer(); private bool mVideoFrameAvailable = false; private int mNumeric = -1; private bool mGreyscale = false; private bool mOverlay = true; public CameraView() { this.InitializeComponent(); timer1.Interval = new TimeSpan(0, 0, 0, 0, 10); timer1.Tick += new EventHandler(timer1_Tick); } public int Numeric { get { return mNumeric; } set { mNumeric = value % 100; if (mNumeric = 0) { if (Camera != null) Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_ON, value % 100); } } } private bool CameraRunning = false; private OptiTrack.NPCamera mCamera; public OptiTrack.NPCamera Camera { get { return mCamera; } set { if (mCamera == value) return; //== Don't do anything if you're assigning the same camera == if (mCamera != null) { //== Shut the selected camera down ==<< if (CameraRunning) { CameraRunning = false; mCamera.Stop(); mCamera.FrameAvailable -= FrameAvailable; } } mCamera = value; if (mCamera == null) { mNumeric = -1; } else { serialLabel.Content = "Camera "+mCamera.SerialNumber.ToString(); //mNumeric.ToString(); } } } private void FrameAvailable(OptiTrack.NPCamera Camera) { mFrameCounter++; try { OptiTrack.NPCameraFrame frame = Camera.GetFrame(0); int id = frame.Id; if (CameraRunning) { GetFrameData(Camera, frame); } frame.Free(); } catch (Exception) { int r = 0; r++; } } private void GetFrameData(OptiTrack.NPCamera camera, OptiTrack.NPCameraFrame frame) { BitmapData bmData = raw.LockBits(new System.Drawing.Rectangle(0, 0, raw.Width, raw.Height), ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppArgb); int stride = bmData.Stride; System.IntPtr bufferPtr = bmData.Scan0; unsafe { byte* buffer = (byte*)(void*)bufferPtr; camera.GetFrameImage(frame, bmData.Width, bmData.Height, bmData.Stride, 32, ref buffer[0]); } raw.UnlockBits(bmData); mVideoFrameAvailable = true; } private void timer1_Tick(object sender, EventArgs e) { if (CameraRunning && mVideoFrameAvailable) { mVideoFrameAvailable = false; cameraImage.Source = Img(raw); mDisplayCounter++; } } private System.Windows.Media.ImageSource Img(System.Drawing.Bitmap img) { System.Drawing.Imaging.BitmapData bmData = img.LockBits(new System.Drawing.Rectangle(0, 0, img.Width, img.Height), System.Drawing.Imaging.ImageLockMode.ReadWrite, System.Drawing.Imaging.PixelFormat.Format32bppPArgb); System.Windows.Media.Imaging.BitmapSource bitmap = System.Windows.Media.Imaging.BitmapSource.Create( img.Width, img.Height, 96, 96, PixelFormats.Bgra32, System.Windows.Media.Imaging.BitmapPalettes.WebPalette, bmData.Scan0, bmData.Stride * bmData.Height, bmData.Stride); img.UnlockBits(bmData); return bitmap; } private void startStopButton_Click(object sender, RoutedEventArgs e) { if (CameraRunning) StopCamera(); else StartCamera(); } public void StartCamera() { if (Camera != null) { mFrameCounter = 0; mDisplayCounter = 0; Camera.FrameAvailable += FrameAvailable; Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0); Camera.SetOption(NP_OPTION_FRAME_DECIMATION, 1); Camera.SetOption(NP_OPTION_INTENSITY, 0); Camera.SetOption(NP_OPTION_EXPOSURE, 10); Camera.SetOption(NP_OPTION_THRESHOLD, 50); Camera.SetOption(NP_OPTION_OBJECT_COLOR_OPTION, 0); SetOverlayOption(); SetGreyscaleOption(); timer1.Start(); Camera.Start(); CameraRunning = true; this.Numeric = mNumeric; startStopButton.Content = "Stop Camera"; } } private void SetGreyscaleOption() { if(mGreyscale) Camera.SetOption(NP_OPTION_VIDEO_TYPE, 1); else Camera.SetOption(NP_OPTION_VIDEO_TYPE, 0); } private void SetOverlayOption() { if(mOverlay) Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 255); else Camera.SetOption(NP_OPTION_TEXT_OVERLAY_OPTION, 0); } public void StopCamera() { if (Camera != null) { Camera.Stop(); timer1.Stop(); CameraRunning = false; Camera.FrameAvailable -= FrameAvailable; Camera.SetOption(NP_OPTION_NUMERIC_DISPLAY_OFF, 0); startStopButton.Content = "Start Camera"; } } private void greyscaleButton_Click(object sender, RoutedEventArgs e) { if(mGreyscale) mGreyscale = false; else mGreyscale = true; SetGreyscaleOption(); } private void OverlayButton_Click(object sender, RoutedEventArgs e) { if(mOverlay) mOverlay = false; else mOverlay = true; SetOverlayOption(); } private void exposureSlider_ValueChanged(object sender, RoutedEventArgs e) { if (mCamera!=null) { mCamera.SetOption(NP_OPTION_EXPOSURE, (int) this.exposureSlider.Value); } } private void thresholdSlider_ValueChanged(object sender, RoutedEventArgs e) { if (mCamera != null) { mCamera.SetOption(NP_OPTION_THRESHOLD, (int)this.thresholdSlider.Value); } } private void optionsButton_Click(object sender, RoutedEventArgs e) { if (!propertyPanel.IsVisible) propertyPanel.Visibility = Visibility.Visible; else propertyPanel.Visibility = Visibility.Collapsed; } } } ================ "CameraView.xaml"

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  • How to know if the client has terminated in sockets

    - by shadyabhi
    Suppose, I have a connected socket after writing this code.. if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0) { perror("accept failed\n"); exit(1); } How can I know at the server side that client has exited. My whole program actually does the following.. Accepts a connection from client Starts a new thread that reads messages from that particular client and then broadcast this message to all the connected clients. If you want to see the whole code... In this whole code. I am also struggling with one more problem that whenever I kill a client with Ctrl+C, my server terminates abruptly.. It would be nice if anyone could suggest what the problem is.. #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <arpa/inet.h> #include <netdb.h> #include <stdio.h> #include <unistd.h> #include <stdlib.h> #include <string.h> #include <signal.h> #include <errno.h> #include <pthread.h> /*CONSTANTS*/ #define DEFAULT_PORT 10000 #define LISTEN_QUEUE_LIMIT 6 #define TOTAL_CLIENTS 10 #define CHAR_BUFFER 256 /*GLOBAL VARIABLE*/ int current_client = 0; int connected_clients[TOTAL_CLIENTS]; extern int errno; void *client_handler(void * socket_d); int main(int argc, char *argv[]) { struct sockaddr_in server_addr;/* structure to hold server's address*/ int socket_d; /* listening socket descriptor */ int port; /* protocol port number */ int option_value; /* needed for setsockopt */ pthread_t tid[TOTAL_CLIENTS]; port = (argc > 1)?atoi(argv[1]):DEFAULT_PORT; /* Socket Server address structure */ memset((char *)&server_addr, 0, sizeof(server_addr)); server_addr.sin_family = AF_INET; /* set family to Internet */ server_addr.sin_addr.s_addr = INADDR_ANY; /* set the local IP address */ server_addr.sin_port = htons((u_short)port); /* Set port */ /* Create socket */ if ( (socket_d = socket(PF_INET, SOCK_STREAM, 0)) < 0) { fprintf(stderr, "socket creation failed\n"); exit(1); } /* Make listening socket's port reusable */ if (setsockopt(socket_d, SOL_SOCKET, SO_REUSEADDR, (char *)&option_value, sizeof(option_value)) < 0) { fprintf(stderr, "setsockopt failure\n"); exit(1); } /* Bind a local address to the socket */ if (bind(socket_d, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) { fprintf(stderr, "bind failed\n"); exit(1); } /* Specify size of request queue */ if (listen(socket_d, LISTEN_QUEUE_LIMIT) < 0) { fprintf(stderr, "listen failed\n"); exit(1); } memset(connected_clients,0,sizeof(int)*TOTAL_CLIENTS); for (;;) { struct sockaddr_in client_addr; /* structure to hold client's address*/ int alen = sizeof(client_addr); /* length of address */ int sd; /* connected socket descriptor */ if ((sd = accept(socket_d, (struct sockaddr *)&client_addr, &alen)) < 0) { perror("accept failed\n"); exit(1); } else printf("\n I got a connection from (%s , %d)\n",inet_ntoa(client_addr.sin_addr),ntohs(client_addr.sin_port)); if (pthread_create(&tid[current_client],NULL,(void *)client_handler,(void *)sd) != 0) { perror("pthread_create error"); continue; } connected_clients[current_client]=sd; current_client++; /*Incrementing Client number*/ } return 0; } void *client_handler(void *connected_socket) { int sd; sd = (int)connected_socket; for ( ; ; ) { ssize_t n; char buffer[CHAR_BUFFER]; for ( ; ; ) { if (n = read(sd, buffer, sizeof(char)*CHAR_BUFFER) == -1) { perror("Error reading from client"); pthread_exit(1); } int i=0; for (i=0;i<current_client;i++) { if (write(connected_clients[i],buffer,sizeof(char)*CHAR_BUFFER) == -1) perror("Error sending messages to a client while multicasting"); } } } } My client side is this (Maye be irrelevant while answering my question) #include <stdio.h> #include <sys/types.h> #include <sys/socket.h> #include <netinet/in.h> #include <netdb.h> #include <string.h> #include <stdlib.h> void error(char *msg) { perror(msg); exit(0); } void *listen_for_message(void * fd) { int sockfd = (int)fd; int n; char buffer[256]; bzero(buffer,256); printf("YOUR MESSAGE: "); fflush(stdout); while (1) { n = read(sockfd,buffer,256); if (n < 0) error("ERROR reading from socket"); if (n == 0) pthread_exit(1); printf("\nMESSAGE BROADCAST: %sYOUR MESSAGE: ",buffer); fflush(stdout); } } int main(int argc, char *argv[]) { int sockfd, portno, n; struct sockaddr_in serv_addr; struct hostent *server; pthread_t read_message; char buffer[256]; if (argc < 3) { fprintf(stderr,"usage %s hostname port\n", argv[0]); exit(0); } portno = atoi(argv[2]); sockfd = socket(AF_INET, SOCK_STREAM, 0); if (sockfd < 0) error("ERROR opening socket"); server = gethostbyname(argv[1]); if (server == NULL) { fprintf(stderr,"ERROR, no such host\n"); exit(0); } bzero((char *) &serv_addr, sizeof(serv_addr)); serv_addr.sin_family = AF_INET; bcopy((char *)server->h_addr, (char *)&serv_addr.sin_addr.s_addr, server->h_length); serv_addr.sin_port = htons(portno); if (connect(sockfd,&serv_addr,sizeof(serv_addr)) < 0) error("ERROR connecting"); bzero(buffer,256); if (pthread_create(&read_message,NULL,(void *)listen_for_message,(void *)sockfd) !=0 ) { perror("error creating thread"); } while (1) { fgets(buffer,255,stdin); n = write(sockfd,buffer,256); if (n < 0) error("ERROR writing to socket"); bzero(buffer,256); } return 0; }

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  • Why my shell program wont open the file got as argument in function "cat"

    - by anna karenina
    I included the code below, sorry to bother you with so much code. Argument parsing is ok, i checked it out with watches. I've put some printfs to check out where the problem may be and it seems that it wont open the file cat receives as argument. i called from shell like "cat -b file" #include <stdio.h> #include <stdlib.h> #include <unistd.h> #include <string.h> #define TRUE 0 #define FALSE 1 void yes(int argc, char *argv[]); int cat(int argc, char *argv[]); //#include "cat.h" //#include "yes.h" //#include"tee.h" char buf[50],c[10], *p2,*p, *pch; int count; char *matrix[20]; void yes(int argc, char *argv[]) { int i; // if (argc >= 2 && *argv[1] == '-') // { //printf("ERROR!"); //} //if (argc == 1) // { while (1) if (puts("y") == EOF) { perror("yes"); exit(FALSE); } // } while (1) for (i = 1; i < argc; i++) if (fputs(argv[i], stdout) == EOF || putchar(i == argc - 1 ? '\n' : ' ') == EOF) { perror("yes"); exit(FALSE); } //exit(TRUE); } int main(int argc, char *argv[]) { //p=(char *)malloc(sizeof(char)*50); do { fprintf (stderr, "$ "); fgets (buf,50,stdin); p=buf; fprintf (stderr, "Comanda primita de la tastatura: "); fputs (buf, stderr); int i=0,j=0; //strcpy(p,buf); strcpy(c,"\0"); while (buf[i] == ' ') { i++; p++; } if (buf[i] == '#') fprintf (stderr, "Nici o comanda, ci e un comentariu!\n"); else { j=0; while (buf[i] != ' ' && buf[i] != '\n') { i++; j++; } strncpy (c,p,j); fprintf (stderr, "%s\n",c); if (strcmp (c,"yes") == 0) { p2 = p+j+1; pch = strtok (p2," "); count = 0; while (pch != NULL) { //printf ("%s\n",pch); matrix[count] = strdup(pch); pch = strtok (NULL, " "); count++; } yes(count, matrix); fprintf (stderr, "Aici se va executa comanda yes\n"); } else if (strcmp (c,"cat") == 0) { p2 = p+j+1; pch = strtok (p2," "); count = 0; while (pch != NULL) { //printf ("%s\n",pch); matrix[count] = strdup(pch); pch = strtok (NULL, " "); count++; } cat(count,matrix); fprintf (stderr, "Aici se va executa comanda cat \n"); } else if (strcmp (c,"tee") == 0) { //tee(); fprintf(stderr, "Aici se va executa comanda tee\n"); } fprintf (stderr, "Aici se va executa comanda basename\n"); strcpy(buf,"\0"); } } while (strcmp(c, "exit") != 0); fprintf (stderr, "Terminat corect!\n"); return 0; } int cat(int argc, char *argv[]) { int c ; opterr = 0 ; optind = 0 ; char number = 0; char squeeze = 0; char marker = 0; fprintf(stderr,"SALUT< SUNT IN FUNCTIZE>\n"); while ((c = getopt (argc, argv, "bnsE")) != -1) switch (c) { case 'b' : number = 1; break; case 'n' : number = 2; break; case 'm' : marker = 1; break; case 's' : squeeze = 1; break; case 'E' : marker = 1; break; } if (optind + 1 != argc) { fprintf (stderr, "\tWrong arguments!\n") ; return -1 ; } FILE * fd = fopen (argv[optind], "r"); printf("am deschis fisierul %s ",argv[optind]); if (fd == NULL) { printf("FISIER NULL asdasdasdasdasd"); return 1; } char line[1025]; int line_count = 1; while (!feof(fd)) { fgets(line, 1025, fd); printf("sunt in while :> %s",line); int len = strlen(line); if (line[len - 1] == '\n') { if(len - 2 >= 0) { if(line[len - 2] == '\r') { line[len - 2] = '\0'; len -= 2; } else { line[len - 1] = '\0'; len -= 1; } } else { line[len - 1] = '\0'; len -= 1; } } if (squeeze == 1 && len == 0) continue; if (number == 1) { fprintf (stdout, "%4d ", line_count); line_count++; } else if (number == 2) { if (len > 0) { fprintf (stdout, "%4d ", line_count); line_count++; } else fprintf (stdout, " "); } fprintf(stdout, "%s", line); if (marker == 1) fprintf(stdout, "$"); fprintf(stdout, "\n"); } fclose (fd); return 0 ; }

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  • Strange (Undefined?) Behavior of Free in C

    - by Chris Cirefice
    This is really strange... and I can't debug it (tried for about two hours, debugger starts going haywire after a while...). Anyway, I'm trying to do something really simple: Free an array of strings. The array is in the form: char **myStrings. The array elements are initialized as: myString[index] = malloc(strlen(word)); myString[index] = word; and I'm calling a function like this: free_memory(myStrings, size); where size is the length of the array (I know this is not the problem, I tested it extensively and everything except this function is working). free_memory looks like this: void free_memory(char **list, int size) { for (int i = 0; i < size; i ++) { free(list[i]); } free(list); } Now here comes the weird part. if (size> strlen(list[i])) then the program crashes. For example, imagine that I have a list of strings that looks something like this: myStrings[0] = "Some"; myStrings[1] = "random"; myStrings[2] = "strings"; And thus the length of this array is 3. If I pass this to my free_memory function, strlen(myStrings[0]) > 3 (4 3), and the program crashes. However, if I change myStrings[0] to be "So" instead, then strlen(myStrings[0]) < 3 (2 < 3) and the program does not crash. So it seems to me that free(list[i]) is actually going through the char[] that is at that location and trying to free each character, which I imagine is undefined behavior. The only reason I say this is because I can play around with the size of the first element of myStrings and make the program crash whenever I feel like it, so I'm assuming that this is the problem area. Note: I did try to debug this by stepping through the function that calls free_memory, noting any weird values and such, but the moment I step into the free_memory function, the debugger crashes, so I'm not really sure what is going on. Nothing is out of the ordinary until I enter the function, then the world explodes. Another note: I also posted the shortened version of the source for this program (not too long; Pastebin) here. I am compiling on MinGW with the c99 flag on. PS - I just thought of this. I am indeed passing numUniqueWords to the free function, and I know that this does not actually free the entire piece of memory that I allocated. I've called it both ways, that's not the issue. And I left it how I did because that is the way that I will be calling it after I get it to work in the first place, I need to revise some of my logic in that function. Source, as per request (on-site): #include <stdio.h> #include <string.h> #include <ctype.h> #include <stdlib.h> #include "words.h" int getNumUniqueWords(char text[], int size); int main(int argc, char* argv[]) { setvbuf(stdout, NULL, 4, _IONBF); // For Eclipse... stupid bug. --> does NOT affect the program, just the output to console! int nbr_words; char text[] = "Some - \"text, a stdin\". We'll have! also repeat? We'll also have a repeat!"; int length = sizeof(text); nbr_words = getNumUniqueWords(text, length); return 0; } void free_memory(char **list, int size) { for (int i = 0; i < size; i ++) { // You can see that printing the values is fine, as long as free is not called. // When free is called, the program will crash if (size > strlen(list[i])) //printf("Wanna free value %d w/len of %d: %s\n", i, strlen(list[i]), list[i]); free(list[i]); } free(list); } int getNumUniqueWords(char text[], int length) { int numTotalWords = 0; char *word; printf("Length: %d characters\n", length); char totalWords[length]; strcpy(totalWords, text); word = strtok(totalWords, " ,.-!?()\"0123456789"); while (word != NULL) { numTotalWords ++; printf("%s\n", word); word = strtok(NULL, " ,.-!?()\"0123456789"); } printf("Looks like we counted %d total words\n\n", numTotalWords); char *uniqueWords[numTotalWords]; char *tempWord; int wordAlreadyExists = 0; int numUniqueWords = 0; char totalWordsCopy[length]; strcpy(totalWordsCopy, text); for (int i = 0; i < numTotalWords; i++) { uniqueWords[i] = NULL; } // Tokenize until all the text is consumed. word = strtok(totalWordsCopy, " ,.-!?()\"0123456789"); while (word != NULL) { // Look through the word list for the current token. for (int j = 0; j < numTotalWords; j ++) { // Just for clarity, no real meaning. tempWord = uniqueWords[j]; // The word list is either empty or the current token is not in the list. if (tempWord == NULL) { break; } //printf("Comparing (%s) with (%s)\n", tempWord, word); // If the current token is the same as the current element in the word list, mark and break if (strcmp(tempWord, word) == 0) { printf("\nDuplicate: (%s)\n\n", word); wordAlreadyExists = 1; break; } } // Word does not exist, add it to the array. if (!wordAlreadyExists) { uniqueWords[numUniqueWords] = malloc(strlen(word)); uniqueWords[numUniqueWords] = word; numUniqueWords ++; printf("Unique: %s\n", word); } // Reset flags and continue. wordAlreadyExists = 0; word = strtok(NULL, " ,.-!?()\"0123456789"); } // Print out the array just for funsies - make sure it's working properly. for (int x = 0; x <numUniqueWords; x++) { printf("Unique list %d: %s\n", x, uniqueWords[x]); } printf("\nNumber of unique words: %d\n\n", numUniqueWords); // Right below is where things start to suck. free_memory(uniqueWords, numUniqueWords); return numUniqueWords; }

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  • Remove accents from String .NET

    - by developerit
    Private Const ACCENT As String = “ÀÁÂÃÄÅàáâãäåÒÓÔÕÖØòóôõöøÈÉÊËèéêëÌÍÎÏìíîïÙÚÛÜùúûüÿÑñÇç” Private Const SANSACCENT As String = “AAAAAAaaaaaaOOOOOOooooooEEEEeeeeIIIIiiiiUUUUuuuuyNnCc” Public Shared Function FormatForUrl(ByVal uriBase As String) As String If String.IsNullOrEmpty(uriBase) Then Return uriBase End If ‘// Declaration de variables Dim chaine As String = uriBase.Trim.Replace(” “, “-”) chaine = chaine.Replace(” “c, “-”c) chaine = chaine.Replace(“–”, “-”) chaine = chaine.Replace(“‘”c, String.Empty) chaine = chaine.Replace(“?”c, String.Empty) chaine = chaine.Replace(“#”c, String.Empty) chaine = chaine.Replace(“:”c, String.Empty) chaine = chaine.Replace(“;”c, String.Empty) ‘// Conversion des chaines en tableaux de caractŠres Dim tableauSansAccent As Char() = SANSACCENT.ToCharArray Dim tableauAccent As Char() = ACCENT.ToCharArray ‘// Pour chaque accent For i As Integer = 0 To ACCENT.Length – 1 ‘ // Remplacement de l’accent par son ‚quivalent sans accent dans la chaŒne de caractŠres chaine = chaine.Replace(tableauAccent(i).ToString(), tableauSansAccent(i).ToString()) Next ‘// Retour du resultat Return chaine End Function

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  • C# HashSet<T>

    - by Ben Griswold
    I hadn’t done much (read: anything) with the C# generic HashSet until I recently needed to produce a distinct collection.  As it turns out, HashSet<T> was the perfect tool. As the following snippet demonstrates, this collection type offers a lot: // Using HashSet<T>: // http://www.albahari.com/nutshell/ch07.aspx var letters = new HashSet<char>("the quick brown fox");   Console.WriteLine(letters.Contains('t')); // true Console.WriteLine(letters.Contains('j')); // false   foreach (char c in letters) Console.Write(c); // the quickbrownfx Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.IntersectWith("aeiou"); foreach (char c in letters) Console.Write(c); // euio Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.ExceptWith("aeiou"); foreach (char c in letters) Console.Write(c); // th qckbrwnfx Console.WriteLine();   letters = new HashSet<char>("the quick brown fox"); letters.SymmetricExceptWith("the lazy brown fox"); foreach (char c in letters) Console.Write(c); // quicklazy Console.WriteLine(); The MSDN documentation is a bit light on HashSet<T> documentation but if you search hard enough you can find some interesting information and benchmarks. But back to that distinct list I needed… // MSDN Add // http://msdn.microsoft.com/en-us/library/bb353005.aspx var employeeA = new Employee {Id = 1, Name = "Employee A"}; var employeeB = new Employee {Id = 2, Name = "Employee B"}; var employeeC = new Employee {Id = 3, Name = "Employee C"}; var employeeD = new Employee {Id = 4, Name = "Employee D"};   var naughty = new List<Employee> {employeeA}; var nice = new List<Employee> {employeeB, employeeC};   var employees = new HashSet<Employee>(); naughty.ForEach(x => employees.Add(x)); nice.ForEach(x => employees.Add(x));   foreach (Employee e in employees) Console.WriteLine(e); // Returns Employee A Employee B Employee C The Add Method returns true on success and, you guessed it, false if the item couldn’t be added to the collection.  I’m using the Linq ForEach syntax to add all valid items to the employees HashSet.  It works really great.  This is just a rough sample, but you may have noticed I’m using Employee, a reference type.  Most samples demonstrate the power of the HashSet with a collection of integers which is kind of cheating.  With value types you don’t have to worry about defining your own equality members.  With reference types, you do. internal class Employee {     public int Id { get; set; }     public string Name { get; set; }       public override string ToString()     {         return Name;     }          public bool Equals(Employee other)     {         if (ReferenceEquals(null, other)) return false;         if (ReferenceEquals(this, other)) return true;         return other.Id == Id;     }       public override bool Equals(object obj)     {         if (ReferenceEquals(null, obj)) return false;         if (ReferenceEquals(this, obj)) return true;         if (obj.GetType() != typeof (Employee)) return false;         return Equals((Employee) obj);     }       public override int GetHashCode()     {         return Id;     }       public static bool operator ==(Employee left, Employee right)     {         return Equals(left, right);     }       public static bool operator !=(Employee left, Employee right)     {         return !Equals(left, right);     } } Fortunately, with Resharper, it’s a snap. Click on the class name, ALT+INS and then follow with the handy dialogues. That’s it. Try out the HashSet<T>. It’s good stuff.

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  • simple C++ hash_set example

    - by celil
    I am new to C++ and STL. I am stuck with the following simple example of a hash set storing custom data structures: #include <iostream> #include <ext/hash_set> using namespace std; using namespace __gnu_cxx; struct trip { int trip_id; int delta_n; int delta_secs; trip(int trip_id, int delta_n, int delta_secs){ this->trip_id = trip_id; this->delta_n = delta_n; this->delta_secs = delta_secs; } }; struct hash_trip { size_t operator()(const trip t) { hash<int> H; return H(t.trip_id); } }; struct eq_trip { bool operator()(const trip t1, const trip t2) { return (t1.trip_id==t2.trip_id) && (t1.delta_n==t2.delta_n) && (t1.delta_secs==t2.delta_secs); } }; int main() { hash_set<trip, hash_trip, eq_trip> trips; trip t = trip(3,2,-1); trip t1 = trip(3,2,0); trips.insert(t); } when I try to compile it, I get the following error message: /usr/include/c++/4.2.1/ext/hashtable.h: In member function ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num_key(const _Key&, size_t) const [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’: /usr/include/c++/4.2.1/ext/hashtable.h:599: instantiated from ‘size_t __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::_M_bkt_num(const _Val&, size_t) const [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hashtable.h:1006: instantiated from ‘void __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::resize(size_t) [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hashtable.h:437: instantiated from ‘std::pair<__gnu_cxx::_Hashtable_iterator<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>, bool> __gnu_cxx::hashtable<_Val, _Key, _HashFcn, _ExtractKey, _EqualKey, _Alloc>::insert_unique(const _Val&) [with _Val = trip, _Key = trip, _HashFcn = hash_trip, _ExtractKey = std::_Identity<trip>, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ /usr/include/c++/4.2.1/ext/hash_set:197: instantiated from ‘std::pair<typename __gnu_cxx::hashtable<_Value, _Value, _HashFcn, std::_Identity<_Value>, _EqualKey, _Alloc>::const_iterator, bool> __gnu_cxx::hash_set<_Value, _HashFcn, _EqualKey, _Alloc>::insert(const typename __gnu_cxx::hashtable<_Value, _Value, _HashFcn, std::_Identity<_Value>, _EqualKey, _Alloc>::value_type&) [with _Value = trip, _HashFcn = hash_trip, _EqualKey = eq_trip, _Alloc = std::allocator<trip>]’ try.cpp:45: instantiated from here /usr/include/c++/4.2.1/ext/hashtable.h:595: error: passing ‘const hash_trip’ as ‘this’ argument of ‘size_t hash_trip::operator()(trip)’ discards qualifiers What am I doing wrong?

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  • clear explanation sought: throw() and stack unwinding

    - by Jerry Gagelman
    I'm not a programmer but have learned a lot watching others. I am writing wrapper classes to simplify things with a really technical API that I'm working with. Its routines return error codes, and I have a function that converts those to strings: static const char* LibErrString(int errno); For uniformity I decided to have member of my classes throw an exception when an error is encountered. I created a class: struct MyExcept : public std::exception { const char* errstr_; const char* what() const throw() {return errstr_;} MyExcept(const char* errstr) : errstr_(errstr) {} }; Then, in one of my classes: class Foo { public: void bar() { int err = SomeAPIRoutine(...); if (err != SUCCESS) throw MyExcept(LibErrString(err)); // otherwise... } }; The whole thing works perfectly: if SomeAPIRoutine returns an error, a try-catch block around the call to Foo::bar catches a standard exception with the correct error string in what(). Then I wanted the member to give more information: void Foo::bar() { char adieu[128]; int err = SomeAPIRoutine(...); if (err != SUCCESS) { std::strcpy(adieu,"In Foo::bar... "); std::strcat(adieu,LibErrString(err)); throw MyExcept((const char*)adieu); } // otherwise... } However, when SomeAPIRoutine returns an error, the what() string returned by the exception contains only garbage. It occurred to me that the problem could be due to adieu going out of scope once the throw is called. I changed the code by moving adieu out of the member definition and making it an attribute of the class Foo. After this, the whole thing worked perfectly: a try-call block around a call to Foo::bar that catches an exception has the correct (expanded) string in what(). Finally, my question: what exactly is popped off the stack (in sequence) when the exception is thrown in the if-block when the stack "unwinds?" As I mentioned above, I'm a mathematician, not a programmer. I could use a really lucid explanation of what goes onto the stack (in sequence) when this C++ gets converted into running machine code.

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