Search Results

Search found 1848 results on 74 pages for 'printf'.

Page 58/74 | < Previous Page | 54 55 56 57 58 59 60 61 62 63 64 65  | Next Page >

• How to prevent users from typing incorrect inputs ?

  - by ZaZu

  Hello, I want the program to loop a scan function if the user types anything else other than numbers.. My code is : do{ printf("Enter rows\n"); scanf("%d",&row); }while(row>='a' && row<='z'); but this code doesnt work .. I keep getting an error when typing in a letter. I tried manipulating around it and the whole thing loops infinitely ... What am I doing wrong ? Please help thanks !

  Read the article

• C - Call a function

  - by Pedro

  Hello. I want to get a value from a function in other function i think i have to call a function in other function, then call it on main, but how? void funcA(PEOPLE people[], int *total){ FILE *fp; char line[100]; fp=fopen("example.txt","r"); if(fp==NULL){ exit(1); } else{ fgets(line, 100, fp);//get a number from the txt total=atoi(linha);//convert to int } } void funcB(PEOPLE people[], int *total){ int i; for(i=0;i<total;i++){ printf("%s\n",people[i].name); } funcA(people,&total); } void main(){ PERSON person[100]; int *total; funcB(people,&total); } What i'm doing wrong?

  Read the article

• which is time consuming construct in following program?

  - by user388338

  while submitting a solution for practise problem 6(odd) i got TLE error but while using using print and scanf in place cin and cout my sol was submitted successfully with 0.77s time..i want to know how can i make it more efficient link to problem is codechef problem 6 #include<iostream> #include<cstdio> using namespace std; int main() {int n,N; scanf("%d",&n); for(int l=0;l<n;l++) { scanf("%d",&N); int i=0,x; if(N<=0) continue; for(;N>=(x=(2<<i));i++); printf("%d",x/2); cout<<"\n"; } }

  Read the article

• I just can't figure out strcat.

  - by Anonymous

  I know I shouldn't be using that function, and I don't care. Last time I checked the spec for strcat, it said something along the lines of updating the first value as well as returning the same. Now, this is a really stupid question, and I want you to explain it like you're talking to a really stupid person. Why won't this work? char* foo="foo"; printf(strcat(foo,"bar")); EDIT: I don't know the difference between char[] and char*. How would I allocate a string of 255 characters? EDIT 2: OK, OK, so char[number] allocates a string of that many bytes? Makes sense. Thanks.

  Read the article

• Reading variable with double float precision from a text file with gnuplot

  - by user3636322

  I have a text file, containing data in 3 columns like below: 0.0100000000 | 0.0058077299 | -0.0000000288 0.0110000000 | 0.0075128707 | -0.0000000373 0.0120000000 | 0.0093579693 | -0.0000000465 I want to get the variables from this file in gnuplot and use them to draw graphs: What I exactly do is like below (e.g: to pick the variable from row 2 column 3): ii= 2 a_0 = system("awk '{ if (NR == " . ii . ") printf \"%f\", $3}' " .datafile) a_0 = a_0+0. but what is written as a_0 is zero! How can I increase the precision to get the exact value?

  Read the article

• Testing for the presence of a character in an string in C

  - by Prab

  What's wrong with this? #include <stdio.h> void main(){ char *s="some text"; printf("%d",is_in(s,'t')); } int is_in(char *s, char c){ while(*s){ if(*s==c) return 1; s++; } return 0; } I get the following compile time error with GCC: test.c:9: error: conflicting types for ‘is_in’ test.c:9: note: an argument type that has a default promotion can’t match an empty parameter name list declaration test.c:5: note: previous implicit declaration of ‘is_in’ was here

  Read the article

• Function in xcode

  - by Joy

  I have a function which have two global variable 1.temp-a nsmutable array 2.j-a int type variable. But i cant access any global variable inside this function. I'm giving the code sample. void print( NSArray *array) { NSEnumerator *enumerator = [array objectEnumerator]; id obj; while ( nil!=(obj = [enumerator nextObject]) ) { NSString *tem=[[obj description] cString]; [temp insertObject:tem atIndex:j]; j=j+1; printf( "%s\n", [[obj description] cString]); } } Looking forward to your response. Thanks in advance..

  Read the article

• What is the reliable way to return error code from an MPI program?

  - by mezhaka

  The MPI standard (page 295) says: Advice to users. Whether the errorcode is returned from the executable or from the MPI process startup mechanism (e.g., mpiexec), is an aspect of quality of the MPI library but not mandatory. Indeed I had no success in running the following code: if(0 == my_rank) { FILE* parameters = fopen("parameters.txt", "r"); if(NULL == parameters) { fprintf(stderr, "Could not open parameters.txt file.\n"); printf("Could not open parameters.txt file.\n"); exit(EXIT_FAILURE); //Tried MPI_Abort() as well } fscanf(parameters, "%i %f %f %f", N, X_DIMENSION_Dp, Y_DIMENSION_Dp, HEIGHT_DIMENSION_Dp); fclose(generation_conf); } I am not able to get the error code back into the shell in order to make a decision on further actions. Neither of two error messages are printed. I think I might write the error codes and messages to a dedicated file. Has anyone ever had a similar problem and what were the options you've considered to do a reliable error reporting?

  Read the article

• function in c language

  - by sandy101

  Hello, I am practice the function in c and come across to the program .... include int main() { float a=15.5; char ch ='C'; printit(a,ch); return 0; } printit(a,ch) { printf("%f\n%c",a,ch); } I want to know that why the above program compile and not give the error as i understood so for is ... 1) The function in c must be declared with the specific prototype (but this program does not contain the prototype ) 2)why the program give the output 'x'for the char variable 3)can the function in c are capable of accepting the value without being declared about type in parameters like what has done in the function declaration .... plz.... help

  Read the article

• portable way to deal with 64/32 bit time_t

  - by MK

  I have some code which is built both on Windows and Linux. Linux at this point is always 32bit but Windows is 32 and 64bit. Windows wants to have time_t be 64 bit and Linux still has it as 32 bit. I'm fine with that, except in some places time_t values are converted to strings. So when time_T is 32 bit it should be done with %d and when it is 64bit with %lld... what is the smart way to do this? Also: any ideas how I may find all places where time_t's are passed to printf-style functions to address this issue?

  Read the article

• Is there a 'catch' with FastFormat?

  - by Roddy

  I just read about the FastFormat C++ i/o formatting library, and it seems too good to be true: Faster even than printf, typesafe, and with what I consider a pleasing interface: // prints: "This formats the remaining arguments based on their order - in this case we put 1 before zero, followed by 1 again" fastformat::fmt(std::cout, "This formats the remaining arguments based on their order - in this case we put {1} before {0}, followed by {1} again", "zero", 1); // prints: "This writes each argument in the order, so first zero followed by 1" fastformat::write(std::cout, "This writes each argument in the order, so first ", "zero", " followed by ", 1); This looks almost too good to be true. Is there a catch? Have you had good, bad or indifferent experiences with it? CW on this question, as there's probably no right answer...

  Read the article

• Why does this C program compile?

  - by AdmiralJonB

  I've just come across someone's C code that I'm confused as to why it is compiling. There are two points I don't understand. First, the function prototype has no parameters compared to the actual function definition. Secondly, the parameter in the function definition doesn't have an type. #include <stdio.h> int func(); int func(param) { return param; } int main() { int bla = func(10); printf("%d",bla); } Could someone please explain to me why this works? I've tested it in a couple of compilers and it works fine.

  Read the article

• Using Classes / OOP in PHP

  - by Alex Demchak

  I'm pretty proficient with PHP, outside of OOP - which I am just now starting to jump in to. I've been watching videos and reading tutorials, but they are all still pretty confusing... If I have FILE 1 (class.time.php) class Time { function GetTime(){ $time = date('H:i:s'); printf($time); } } and then in a nother php page I've got FILE 2 (page.php) I can do include('class.time.php'); and then anywhere in this page I can then do $time = new Time; //Calling the class and setting the class to a variable $time->GetTime(); //This is BASICALLY saying (run the 'GetTime' function in the 'Time Class' My main question is, is the comment above (This is BASICALLY saying.....) correct? or is there a better way to think of it?

  Read the article

• C++: use array of strings wrapped in namespace?

  - by John D.

  I got the following code, wishing to wrap a group of strings nicely in a namespace: namespace msgs { const int arr_sz = 3; const char *msg[arr_sz] = {"blank", "blank", "blank" }; msg[0] = "Welcome, lets start by getting a little info from you!\n"; msg[1] = "Alright, bla bla bla.."; msg[2] = "etc."; } The code inside works nicely inside a function, but I don't know how to return an array from it. The namespace idea LOOKS fine, but it returns on the last three lines: error: expected constructor, destructor, or type conversion before ‘=’ token Why can't I define the array inside a namespace, do I need to do something first? It's nice because I can call it like printf(msgs::msg[1]) etc. I want to do this I just can't wrap my head around what's wrong :(

  Read the article

• MACRO Question: Returning pointer to a certain value

  - by Andrei Ciobanu

  Is it possible to write a MACRO that has a type and a value as its input parameters (MACRO(type,value)), and returns a valid pointer to a location that holds the submitted value. This macro should perform like the following function, but in a more generic manner: int *val_to_ptr(int val){ int *r = NULL; r = nm_malloc(sizeof(*r)); *r = val; return r; } Where nm_malloc() is a failsafe malloc. The Macro usage should be compatible with this usage: printf("%d",*MACRO(int,5)); Is it possible to achieve that ?

  Read the article

• Function argument treated as undeclared

  - by Mikulas Dite

  I've prepared this simple example which is not working for me #include <stdio.h> #include <stdlib.h> FILE *fp; char filename[] = "damy.txt"; void echo (char[] text) { fp = fopen(filename, "a"); fwrite(text, 1, strlen(text), fp); fclose(fp); printf(text); } int main () { echo("foo bar"); return 0; } It's supposed to write both to command window and to file. However, this gives compilation error - the text used in echo() is not declared. Does c need another declaration of the variable?

  Read the article

• this == null; surely not, but yes

  - by pm100

  I would have said that this will segfault but apparently not #include <stdio.h> class foo { public: bool thingy() {return this == 0;}; }; int main() { foo *f = 0; if(f->thingy()) printf("eating hat\n"); } I just expect that 0-xxx will never work. I assume that if we had to do some vtabling it would fail; obviously cannot access any member variables either edit; sorry - no question there. THe question is "are you surprised like me?" and it seems the answer is yes. even though nobody said yes. I got a) of course this will work b) of course this will never work c) it is undefined behavior; your mileage will vary

  Read the article

• Referencing an array to a pointer

  - by james

  I want to refer a pointer to an array by another pointer. Example: void exp() { double var[2]; exp1(&var[0]); printf("\n varvalue is %lf\n",var[0]); } void exp1(double *var) { //updating the value *var[0]=4.0; exp2(&var[0]); } void exp2(double *var) { *var[0]=7.0; } This should update the value as 7.0(the last update).I am getting an array like invalid argument type of unary(*) . How can i correct this?where i am going wrong here?

  Read the article

• Is there any way to print the actual query that mysqli->execute() makes?

  - by 0plus1

  I have a complex query that gets executed like this: if ($stmt = $dbi->prepare($pt_query)) { $stmt->bind_param('ssssssssi', $snome,$scognome,$ssocieta,$svia,$slocalita,$sprovincia,$scap,$stelefono,$sfax,$uid); $stmt->execute(); echo $dbi->error; $stmt->close(); } else { printf("Error -> %s\n", $dbi->error); } This thing is failing without any error, it simply doesn't update the database. Since there is a ton of data that gets treated before this thing I would like to know if there is any way to show the actual query that mysqli is executing in order to understand where the problem is. Thank you.

  Read the article

• dreferencing 2 d array

  - by ashish-sangwan

  Please look at this peice of code :- #include<stdio.h> int main() { int arr[2][2]={1,2,3,4}; printf("%d %u %u",**arr,*arr,arr); return 0; } When i compiled and executed this program i got same value for arr and *arr which is the starting address of the 2 d array. For example:- 1 3214506 3214506 My question is why does dereferencing arr ( *arr ) does not print the value stored at the address contained in arr ?

  Read the article

• What is wrong with this c strdup code?

  - by bstullkid

  Consider this code: char *strs[] = { "string1", "string2", NULL }; char *ptr1 = NULL, *ptr2 = NULL, *tmp; short iter = 0; tmp = ptr1; while (iter < 2) { tmp = strdup(strs[iter]); tmp = ptr2; iter++; } printf("1: %s\n2: %s\n", ptr1, ptr2); I want this to output "string1\nstring2\n" however str1 and str2 remain null. What am I doing wrong?

  Read the article

• Extract data from uint8 to double

  - by HADJ AMOR HASSEN

  I have a C function receiving a uint8 pointer with another parameter which is its size (number of bytes). I want to extract double data from this buffer. Here is my code: Write(uint8* data, uint8 size) /* data and size are given by a callback to my function)*/ { double d; for (i = 0; i < size; i++) { d = ((double*)&data)[i]; printf(" d = %d\n"); } } The problem is that I am not receiving what I am sending within an external hardware. I guess that my cast is wrong. I tried other methods but without any good result. I am still not able to get what I send.

  Read the article

• C: stdin and std* errs

  - by user355926

  I want to my manipulate Stdin, then Std* but some errs: $ gcc testFd.c testFd.c:9: error: initializer element is not constant testFd.c:9: warning: data definition has no type or storage class testFd.c:10: error: redefinition of `fd' testFd.c:9: error: `fd' previously defined here testFd.c:10: error: `mode' undeclared here (not in a function) testFd.c:10: error: initializer element is not constant testFd.c:10: warning: data definition has no type or storage class testFd.c:12: error: syntax error before string constant $ cat testFd.c #include <stdio.h> #include <sys/ioctl.h> int STDIN_FILENO = 1; // I want to access typed // Shell commands, dunno about the value: unsigned long F_DUPFD; fd = fcntl(STDIN_FILENO, F_DUPFD, 0); fd = open("/dev/fd/0", mode); printf("STDIN = %s", fd);

  Read the article

• argument promotions in C function calls

  - by HaoCheng

  I learned from ----As to when default promotions kick in: default argument promotions are used exactly when the expected type of the argument is unknown, which is to say when there's no prototype or when the argument is variadic. But an example confusing me is: void func(char a, char b) { printf("a=%p,b=%p\n",&a,&b); } int main(void) { char a=0x11,b=0x22; func(a,b); return 0; } It is cleard in the above example: when calling func in main, there is no need to promote the arguments a and b, but the output shows &a = &b +4 not &a = &b+1. If no promotion occured, why 4 bytes between two CHAR argument?

  Read the article

• Has anyone properly interpreted HTTP request based on this demo of winpcap?

  - by httpinterpret

  The example is here, and I tried it by changing the filter to tcp and dst port 80 and the following: void packet_handler(u_char *param, const struct pcap_pkthdr *header, const u_char *pkt_data) { .... ip_len = (ih->ver_ihl & 0xf) * 4; tcp_len = (((u_char*)ih)[ip_len + 12] >> 4) * 4; tcpPayload = (u_char*)ih + ip_len + tcp_len; /* start of url - skip "GET " */ url = tcpPayload + 4; end_url = strchr((char*)url, ' '); url_length = end_url - url; final_url = (u_char*)malloc(url_length + 1); strncpy((char*)final_url, (char*)url, url_length); final_url[url_length] = '\0'; printf("%s\n", final_url); .... } But through debug, I see tcpPayload is full of messy code,not supposed "GET ..." stuff. What's wrong with my implement?

  Read the article

< Previous Page | 54 55 56 57 58 59 60 61 62 63 64 65  | Next Page >