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• Device drivers and Windows

  - by b-gen-jack-o-neill

  Hi, I am trying to complete the picture of how the PC and the OS interacts together. And I am at point, where I am little out of guess when it comes to device drivers. Please, don´t write things like its too complicated, or you don´t need to know when using high programming laguage and winapi functions. I want to know, it´s for study purposes. So, the very basic structure of how OS and PC (by PC I mean of course HW) is how I see it is that all other than direct CPU commands, which can CPU do on itself (arithmetic operation, its registers access and memory access) must pass thru OS. Mainly becouse from ring level 3 you cannot use in and out intructions which are used for acesing other HW. I know that there is MMIO,but it must be set by port comunication first. It was not like this all the time. Even I am bit young to remember MSDOS, I know you could access HW directly, becouse there ws no limitation, no ring mode. So you could to write string to diplay use wheather DOS function, or directly acess video card memory and write it by yourself. But as OS developed, there is no longer this possibility. But it is fine, since OS now handles all the HW comunication, and frankly it more convinient and much more safe (I would say the only option) in multitasking environment. So nowdays you instead of using int instructions to use BIOS mapped function or DOS function you call dll which internally than handles everything you don´t need to know about. I understand this. I also undrstand that device drivers is the piece of code that runs in ring level 0, so it can do all the HW interactions. But what I don´t understand is connection between OS and device driver. Let´s take a example - I want to make a sound card make a sound. So I call windows API to acess sound card, but what happens than? Does windows call device drivers to do so? But if it does call device driver, does it mean, that all device drivers which can be called by winAPI function, must have routines named in some specific way? I mean, when I have new sound card, must its drivers have functions named same as the old one? So Windows can actually call the same function from its perspective? But if Windows have predefined sets of functions requored by device drivers, that it cannot use new drivers that doesent existed before last version of OS came out. Please, help me understand this mess. I am really getting mad. Thanks.

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• Unexpected return value

  - by Nicholas Gibson

  Program stopped compiling at this point: What is causing this error? (Error is at the bottom of post) public class JFrameWithPanel extends JFrame implements ActionListener, ItemListener { int packageIndex; double price; double[] prices = {49.99, 39.99, 34.99, 99.99}; DecimalFormat money = new DecimalFormat("$0.00"); JLabel priceLabel = new JLabel("Total Price: "+price); JButton button = new JButton("Check Price"); JComboBox packageChoice = new JComboBox(); JPanel pane = new JPanel(); TextField text = new TextField(5); JButton accept = new JButton("Accept"); JButton decline = new JButton("Decline"); JCheckBox serviceTerms = new JCheckBox("I Agree to the Terms of Service.", false); JTextArea termsOfService = new JTextArea("This is a text area", 5, 10); public JFrameWithPanel() { super("JFrame with Panel"); setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); pane.add(packageChoice); setContentPane(pane); setSize(250,250); setVisible(true); packageChoice.addItem("A+ Certification"); packageChoice.addItem("Network+ Certification "); packageChoice.addItem("Security+ Certifictation"); packageChoice.addItem("CIT Full Test Package"); pane.add(button); button.addActionListener(this); pane.add(text); text.setEditable(false); text.setBackground(Color.WHITE); text.addActionListener(this); pane.add(termsOfService); termsOfService.setEditable(false); termsOfService.setBackground(Color.lightGray); pane.add(serviceTerms); serviceTerms.addItemListener(this); pane.add(accept); accept.addActionListener(this); pane.add(decline); decline.addActionListener(this); } public void actionPerformed(ActionEvent e) { packageIndex = packageChoice.getSelectedIndex(); price = prices[packageIndex]; text.setText("$"+price); Object source = e.getSource(); if(source == accept) { if(serviceTerms.isSelected() = false) // line 79 { JOptionPane.showMessageDialog(null,"Please accept the terms of service."); } else { JOptionPane.showMessageDialog(null,"Thanks."); } } } Error: \Desktop\Java Programming\JFrameWithPanel.java:79: unexpected type required: variable found : value if(serviceTerms.isSelected() = false) ^ 1 error

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• Java Flow Control Problem

  - by Kyle_Solo

  I am programming a simple 2d game engine. I've decided how I'd like the engine to function: it will be composed of objects containing "events" that my main game loop will trigger when appropriate. A little more about the structure: Every GameObject has an updateEvent method. objectList is a list of all the objects that will receive update events. Only objects on this list have their updateEvent method called by the game loop. I’m trying to implement this method in the GameObject class (This specification is what I’d like the method to achieve): /** * This method removes a GameObject from objectList. The GameObject * should immediately stop executing code, that is, absolutely no more * code inside update events will be executed for the removed game object. * If necessary, control should transfer to the game loop. * @param go The GameObject to be removed */ public void remove(GameObject go) So if an object tries to remove itself inside of an update event, control should transfer back to the game engine: public void updateEvent() { //object's update event remove(this); System.out.println("Should never reach here!"); } Here’s what I have so far. It works, but the more I read about using exceptions for flow control the less I like it, so I want to see if there are alternatives. Remove Method public void remove(GameObject go) { //add to removedList //flag as removed //throw an exception if removing self from inside an updateEvent } Game Loop for(GameObject go : objectList) { try { if (!go.removed) { go.updateEvent(); } else { //object is scheduled to be removed, do nothing } } catch(ObjectRemovedException e) { //control has been transferred back to the game loop //no need to do anything here } } // now remove the objects that are in removedList from objectList 2 questions: Am I correct in assuming that the only way to implement the stop-right-away part of the remove method as described above is by throwing a custom exception and catching it in the game loop? (I know, using exceptions for flow control is like goto, which is bad. I just can’t think of another way to do what I want!) For the removal from the list itself, it is possible for one object to remove one that is farther down on the list. Currently I’m checking a removed flag before executing any code, and at the end of each pass removing the objects to avoid concurrent modification. Is there a better, preferably instant/non-polling way to do this?

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• How can I obtain the IPv4 address of the client?

  - by Dr Dork

  Hello! I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code setup to listen for incoming TCP connection requests from clients after the parent socket has been created and is set to listen... int sockfd, newfd; unsigned int len; socklen_t sin_size; char msg[]="Test message sent"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char ip[INET6_ADDRSTRLEN]; . . //parent socket creation and listen code omitted for simplicity . //wait for connection requests from clients while(1) { //Returns the socketID and address of client connecting to socket if( ( newfd = accept(sockfd, (struct sockaddr *)&client, &len) ) == -1 ){ perror("Accept"); exit(-1); } if( (rv = recv(newfd, buf, MAXLEN-1, 0 )) == -1) { perror("Recv"); exit(-1); } struct sockaddr_in *clientAddr = ( struct sockaddr_in *) get_in_addr((struct sockaddr *)&client); inet_ntop(client.ss_family, clientAddr, ip, sizeof ip); printf("Receive from %s: query type is %s\n", ip, buf); if( ( st = send(newfd, msg, strlen(msg), 0)) == -1 ) { perror("Send"); exit(-1); } //ntohs is used to avoid big-endian and little endian compatibility issues printf("Send %d byte to port %d\n", ntohs(clientAddr->sin_port) ); close(newfd); } } I found the get_in_addr function online and placed it at the top of my code and use it to obtain the IP address of the client connecting... // get sockaddr, IPv4 or IPv6: void *get_in_addr(struct sockaddr *sa) { if (sa->sa_family == AF_INET) { return &(((struct sockaddr_in*)sa)->sin_addr); } return &(((struct sockaddr_in6*)sa)->sin6_addr); } but the function always returns the IPv6 IP address since thats what the sa_family property is set as. My question is, is the IPv4 IP address stored anywhere in the data I'm using and, if so, how can I access it? Thanks so much in advance for all your help!

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• How do I make the info window editable in the Google Maps API?

  - by zjm1126

  I would like to make the info window editable when i click on it. This is my code: <!DOCTYPE html PUBLIC "-//WAPFORUM//DTD XHTML Mobile 1.0//EN" "http://www.wapforum.org/DTD/xhtml-mobile10.dtd"> <html xmlns="http://www.w3.org/1999/xhtml" > <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <meta name="viewport" content="width=device-width,minimum-scale=0.3,maximum-scale=5.0,user-scalable=yes"> </head> <body onload="initialize()" onunload="GUnload()"> <style type="text/css"> *{ margin:0; padding:0; } </style> <!--<div style="width:100px;height:100px;background:blue;"> </div>--> <div id="map_canvas" style="width: 500px; height: 300px;"></div> <div class=b style="width: 20px; height: 20px;background:red;position:absolute;left:700px;top:200px;"></div> <div class=b style="width: 20px; height: 20px;background:red;position:absolute;left:700px;top:200px;"></div> <script src="jquery-1.4.2.js" type="text/javascript"></script> <script src="jquery-ui-1.8rc3.custom.min.js" type="text/javascript"></script> <script src="http://maps.google.com/maps?file=api&amp;v=2&amp;key=ABQIAAAA-7cuV3vqp7w6zUNiN_F4uBRi_j0U6kJrkFvY4-OX2XYmEAa76BSNz0ifabgugotzJgrxyodPDmheRA&sensor=false"type="text/javascript"></script> <script type="text/javascript"> var aFn; //********** function initialize() { if (GBrowserIsCompatible()) { var map = new GMap2(document.getElementById("map_canvas")); var center=new GLatLng(39.9493, 116.3975); map.setCenter(center, 13); aFn=function(x,y){ var point =new GPoint(x,y) point = map.fromContainerPixelToLatLng(point); //console.log(point.x+" "+point.y) var marker = new GMarker(point,{draggable:true}); GEvent.addListener(marker, "click", function() { marker.openInfoWindowHtml("<b>wwww</b>"); }); map.addOverlay(marker); /********** var marker = new GMarker(point, {draggable: true}); GEvent.addListener(marker, "dragstart", function() { map.closeInfoWindow(); }); GEvent.addListener(marker, "dragend", function() { marker.openInfoWindowHtml("????..."); }); map.addOverlay(marker); //*/ } $(".b").draggable({ revert: true, revertDuration: 0 }); $("#map_canvas").droppable({ drop: function(event,ui) { //console.log(ui.offset.left+' '+ui.offset.top) aFn(event.pageX-$("#map_canvas").offset().left,event.pageY-$("#map_canvas").offset().top); } }); } } </script> </body> </html>

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• Searching a Better Solution with Delegates

  - by spagetticode

  Hey All, I am a newbie in C# and curious about the better solution of my case. I have a method which gets the DataTable as a parameter and creates a List with MyClass's variables and returns it. public static List<Campaigns> GetCampaignsList(DataTable DataTable) { List<Campaigns> ListCampaigns = new List<Campaigns>(); foreach (DataRow row in DataTable.Rows) { Campaigns Campaign = new Campaigns(); Campaign.CampaignID = Convert.ToInt32(row["CampaignID"]); Campaign.CustomerID = Convert.ToInt32(row["CustomerID"]); Campaign.ClientID = Convert.ToInt32(row["ClientID"]); Campaign.Title = row["Title"].ToString(); Campaign.Subject = row["Subject"].ToString(); Campaign.FromName = row["FromName"].ToString(); Campaign.FromEmail = row["FromEmail"].ToString(); Campaign.ReplyEmail = row["ReplyEmail"].ToString(); Campaign.AddDate = Convert.ToDateTime(row["AddDate"]); Campaign.UniqueRecipients = Convert.ToInt32(row["UniqueRecipients"]); Campaign.ClientReportVisible = Convert.ToBoolean(row["ClientReportVisible"]); Campaign.Status = Convert.ToInt16(row["Status"]); ListCampaigns.Add(Campaign); } return ListCampaigns; } And one of my another DataTable method gets the DataTable from the database with given parameters. Here is the method. public static DataTable GetNewCampaigns() { DataTable dtCampaigns = new DataTable(); Campaigns Campaigns = new Campaigns(); dtCampaigns = Campaigns.SelectStatus(0); return dtCampaigns; } But the problem is that, this GetNewCampaigns method doesnt take parameters but other methods can take parameters. For example when I try to select a campaign with a CampaignID, I have to send CampaignID as parameter. These all Database methods do take return type as DataTable but different number of parameters. public static DataTable GetCampaignDetails(int CampaignID) { DataTable dtCampaigns = new DataTable(); Campaigns Campaigns = new Campaigns(); dtCampaigns = Campaigns.Select(CampaignID); return dtCampaigns; } At the end, I want to pass a Delegate to my first GetCampaignList Method as parameter which will decide which Database method to invoke. I dont want to pass DataTable as parameter as it is newbie programming. Could you pls help me learn some more advance features. I searched over it and got to Func< delegate but could not come up with a solution.

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• Windows MAchine Debugging

  - by PrettyFlower

  I've been learning how to program for Windows for some time now and am getting pretty comfy with COM. I had thought to go over to Linux and do some C++ programming there and I wished to run Rosetta Commons so I installed Fedora. I had tried installing Ubuntu a few months ago and things got messy. I had a glitch, maybe caused by one of the live cd creators, my video card or something I don't know. Who Crashed suggested it was my video card and I had regular messages about ntfs.sys and page file issues. At any rate I just installed Fedora and the same thing is happening again. I would like to think with the twenty five years of doing this that I might finally make some headway into debugging my system. I think I may have overlooked a lot of what could be done in favor of simply uninstalling, reinstalling and formatting and starting from scratch. I have opened up the folder windows debugging tools, quite accidentally and just before I was going to clean sweep again, and I found KD and WinDbg. I had never seen these before and I felt that maybe I should look into this. I am quite familiar with the modern machine that is known as the computer, I know what a Kernel is and am now pretty familiar with at the very least Windows Operating System Services. I wish to begin tracking my own machines errors. I understand that most kernel debugging is done on a second machine but I don't have one. And also I understand the goal of the debugger seems to be less about run of the mill errors and more about development time strategies but I'm sure there is more to this. This is my first go at this and I thought maybe I could get some suggestions on where to go from here. I would really like to learn ways to fix my machine and also maybe pick up some tricks on the dev side as well. I hope this isn't too broad a question or too generalized. I'm really just looking for the keywords and an overview of the more routine strategies used. thx

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• How do you return a string from a function correctly in Dynamic C?

  - by aquanar

  I have a program I am trying to debug, but Dynamic C apparently treats strings differently than normal C does (well, character arrays, anyway). I have a function that I made to make an 8 character long (well, 10 to include the \0 ) string of 0s and 1s to show me the contents of an 8-bit char variable. (IE, I give it the number 13, it returns the string "0001101\0" ) When I use the code below, it prints out !{happy face] 6 times (well, the second one is the happy face alone for some reason), each return comes back as 0xDEAE or "!\x02. I thought it would dereference it and return the appropriate string, but it appears to just be sending the pointer and attempting to parse it. This may seem silly, but my experience was actually in C++ and Java, so going back to C brings up a few issues that were dealt with in later programming languages that I'm not entirely sure how to deal with (like the lack of string variables). How could I fix this code, or how would be a better way to do what I am trying to do (I thought maybe sending in a pointer to a character array and working on it from the function might work, but I thought I should ask to see if maybe I'm just trying to reinvent the wheel). Currently I have it set up like this: this is an excerpt from the main() display[0] = '\0'; for(i=0;i<6;i++) { sprintf(s, "%s ", *char_to_bits(buffer[i])); strcat(display, s); } DispStr(8,5, display); and this is the offending function: char *char_to_bits(char x) { char bits[16]; strcpy(bits,"00000000\0"); if (x & 0x01) bits[7]='1'; if (x & 0x02) bits[6]='1'; if (x & 0x04) bits[5]='1'; if (x & 0x08) bits[4]='1'; if (x & 0x10) bits[3]='1'; if (x & 0x20) bits[2]='1'; if (x & 0x40) bits[1]='1'; if (x & 0x80) bits[0]='1'; return bits; } and just for the sake of completion, the other function is used to output to the stdio window at a specific location: void DispStr(int x, int y, char *s) { x += 0x20; y += 0x20; printf ("\x1B=%c%c%s", x, y, s); }

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• How do I access the enumerated item with an indexer and assign array string to it for display?

  - by g00p3k

  EDITED: Updated 3/23/09. See rest of post at bottom. I'm still having trouble with the indexer. Anymore help or examples would really help me out. Write a class, MyCourses, that contains an enumeration of all the courses that you are currently taking. This enum should be nested inside of your class MyCourses. Your class should also have an array field that provides a short description (as a String) of each of your courses. Write an indexer that takes one of your enumerated courses as an index and returns the String description of the course. Write a class MyFriends that contains an indexer that provides access to the names of your friends. namespace IT274_Unit4Project { public class MyCourses { // enumeration that contains an enumeration of all the courses that // student is currently enrolled in public enum CourseName {IT274= 0,CS210 = 1} // array field that provides short description for each of classes, // returns string description of the course private String[] courseDescription = {"Intermediate C#: Teaches intermediate elements of C# programming and software design", "Career Development Strategies: Teaches principles for career progression, resume preparation, and overall self anaylsis"}; // indexer that takes one of the enumerated courses as an index // and returns the String description of the course public String this[CourseName index] { get { if (index == 1) return courseDescription[0]; else return courseDescription[1]; } set { if (index == 1) courseDescription[0] = value; else courseDescription[1] = value; } } } }//end public class MyCourses I'm working on this homework project and having trouble understanding the text explaining how to correctly take the accessed value of the enumeration and then apply the string array value to it. Can you please help me understand this? The text we are using is very difficult and poorly written for a beginner to understand, so I'm kind of on my own here. I've got the first parts written, but need some help on the accessing of the enumeration value and assigning, i think i'm close, but don't understand how to properly get and set the values on this. Please do not provide me with direct code answers, unless a MSDN style explanation that is generalized and not specific to my project. ie: public class MyClass { string field1; string field2; //properties public string Value1 get etc... Thanks!

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• Advice needed: stay with Java team or move to C++ team?

  - by user68759

  Some background - I have been programming in Java as a professional for the last few years. This is mainly using Java SE. I have also touched bits and pieces of other various Java technologies and have some basic knowledge about them. I consider my self as an intermediate Java programmer. I like Java very much. I think it is only going to get bigger. Recently, my manager asked my opinion on whether I would like to be transferred to another team within the company that is developing a product in C++. This is mainly because my current Java team simply didn't make enough money due to poor sales and the economic downturn. Now, I have never had any experience with C++ nor have I ever coded a single line of code in C++. I have always wanted to learn it and now is my chance. But I really want to make sure I get benefit out of it in the future, in the sense that I will have the skills that will still be on-demand in the future. So, what do you experts think? Is C++ still the language to learn these days to secure yourself for the future? What will I learn more in C++ but not in Java? And are they worthy to learn considering the current and possible future demands in IT industry? (Apart from the obvious more control over memory management and something along that line.) What is a good excuse to refuse the offer in order to stay with the Java team? I don't want to blatantly refuse it because you can never predict the future and I could possibly come back to my manager in the future and ask him to transfer me to the C++ team. How do I say it nicely that I am taking the offer but I would like to still be involved with Java one way or another, such as when there is a new Java project I would like to be considered. I have to admit that I am kind of 50-50 at the moment. I want to learn C++ for the sake of improving my skills and also helping my company to reduce the fund required for the Java team. But it is also hard for me to leave Java because I know Java is going to get bigger, so I am afraid of getting behind when I start concentrating on C++. I could, of course, decide to just join the C++ team, and then spend my free time reading about Java to keep in touch with it, but I thought I would ask anyway in case some people can point out the strong points of either over the other given the current and possibly future circumstances.

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• What's the fastest lookup algorithm for a key, pair data structure (i.e, a map)?

  - by truncheon

  In the following example a std::map structure is filled with 26 values from A - Z (for key) and 0 – 26 for value. The time taken (on my system) to lookup the last entry (10000000 times) is roughly 250 ms for the vector, and 125 ms for the map. (I compiled using release mode, with O3 option turned on for g++ 4.4) But if for some odd reason I wanted better performance than the std::map, what data structures and functions would I need to consider using? I apologize if the answer seems obvious to you, but I haven't had much experience in the performance critical aspects of C++ programming. #include <ctime> #include <map> #include <vector> #include <iostream> struct mystruct { char key; int value; mystruct(char k = 0, int v = 0) : key(k), value(v) { } }; int find(const std::vector<mystruct>& ref, char key) { for (std::vector<mystruct>::const_iterator i = ref.begin(); i != ref.end(); ++i) if (i->key == key) return i->value; return -1; } int main() { std::map<char, int> mymap; std::vector<mystruct> myvec; for (int i = 'a'; i < 'a' + 26; ++i) { mymap[i] = i - 'a'; myvec.push_back(mystruct(i, i - 'a')); } int pre = clock(); for (int i = 0; i < 10000000; ++i) { find(myvec, 'z'); } std::cout << "linear scan: milli " << clock() - pre << "\n"; pre = clock(); for (int i = 0; i < 10000000; ++i) { mymap['z']; } std::cout << "map scan: milli " << clock() - pre << "\n"; return 0; }

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• [C#] How to do a search from a list with non-prefix keywords

  - by aNui

  First of all, sorry if my english or my post got any mistakes. I am programming a program to search the name from the list and I need to find them if the keyword is not in front of the names (that's what I mean non-prefix) e.g. if I my list is the music instruments and I type "guit" to the search textbox. It should find the names "Guitar, Guitarrón, Acoustic Guitar, Bass Guitar, ..." or something like this Longdo Dictionary's search suggestion. here is my simple and stupid algorithm (that's all I can do) const int SEARCHROWLIMIT = 30; private string[] DoSearch(string Input, string[] ListToSearch) { List<string> FoundNames = new List<string>(); int max = 0; bool over = false; for (int k = 0; !over; k++) { foreach (string item in ListToSearch) { max = (max > item.Length) ? max : item.Length; if (k > item.Length) continue; if (k >= max) { over = true; break; } if (!Input.Equals("Search") && item.Substring(k, item.Length - k).StartsWith(Input, StringComparison.OrdinalIgnoreCase)) { bool exist = false; int i = 0; while (!exist && i < FoundNames.Count) { if (item.Equals(FoundNames[i])) { exist = true; break; } i++; } if (!exist && FoundNames.Count < SEARCHROWLIMIT) FoundNames.Add(item); else if (FoundNames.Count >= SEARCHROWLIMIT) over = true; } } } return FoundNames.ToArray(); } I think this algorithm is too slow for a large number of names and after several trial-and-error, I decided to add SEARCHROWLIMIT to breaks the operation And I also think there're some readymade methods that can do that. And another problem is I need to search music instruments by a category like strings, percussions, ... and by the country of origins. So I need to search them with filter by type and country. please help me. P.S. Me and my friends are just student from Thailand and developing the project to compete in Microsoft Imagine Cup 2010 and please become fan on our facebook page [KRATIB][3]. And we're so sorry we don't have much information in English but you can talk to us in English.

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• How can I obtain the IP address of my server program?

  - by Dr Dork

  Hello! This question is related to another question I just posted. I'm prepping for a simple work project and am trying to familiarize myself with the basics of socket programming in a Unix dev environment. At this point, I have some basic server side code and client side code setup to communicate. Currently, my client code successfully connects to the server code and the server code sends it a test message, then both quit out. Perfect! That's exactly what I wanted to accomplish. Now I'm playing around with the functions used to obtain info about the two environments (server and client). I'd like to obtain my server program's IP address. Here's the code I currently have to do this, but it's not working... int sockfd; unsigned int len; socklen_t sin_size; char msg[]="test message"; char buf[MAXLEN]; int st, rv; struct addrinfo hints, *serverinfo, *p; struct sockaddr_storage client; char s[INET6_ADDRSTRLEN]; char ip[INET6_ADDRSTRLEN]; //zero struct memset(&hints,0,sizeof(hints)); hints.ai_family = AF_UNSPEC; hints.ai_socktype = SOCK_STREAM; hints.ai_flags = AI_PASSIVE; //get the server info if((rv = getaddrinfo(NULL, SERVERPORT, &hints, &serverinfo ) != 0)){ perror("getaddrinfo"); exit(-1); } // loop through all the results and bind to the first we can for( p = serverinfo; p != NULL; p = p->ai_next) { //Setup the socket if( (sockfd = socket( p->ai_family, p->ai_socktype, p->ai_protocol )) == -1 ) { perror("socket"); continue; } //Associate a socket id with an address to which other processes can connect if(bind(sockfd, p->ai_addr, p->ai_addrlen) == -1){ close(sockfd); perror("bind"); continue; } break; } if( p == NULL ){ perror("Fail to bind"); } inet_ntop(p->ai_family, get_in_addr((struct sockaddr *)p->ai_addr), s, sizeof(s)); printf("Server has TCP Port %s and IP Address %s\n", SERVERPORT, s); and the output for the IP is always empty... server has TCP Port 21412 and IP Address :: any ideas for what I'm missing? thanks in advance for your help! this stuff is really complicated at first.

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• jQuery getScript function with frames

  - by user210099

  Hello.. I'm a novice at Javascript/Jquery programming, so an apology if this is a simple/silly question. I am trying to use the jQuery .getScript() function to refresh part of an existing webpage. This webpage must be run on a local file system, and a large amount of the formatting is done using frames. Right now, there’s three main frames- a sidebar which displays possible “scopes” to choose from, a main frame which displays the majority of the contents of the webpage, and a footer frame. The main entry into the page is in an index.html file, which loads a sidebar.html, main.html, and footer.html file into each of the respective frames. In turn, the main.html has a number of javascript files which it loads, the main being a main.js, which contains numerous functions to format/process the contents for this main window. After loading this javascript file, main.html loads a few javascript files, which contain the data which is going to be displayed in the main frame. These files that are loaded have a fixed data structure, and are dependent on the functions that were loaded by the main.js file. Loading the webpage works fine now, but when a user tries to switch to another “scope”, the whole webpage is reloaded to make the switch. The only difference in the webpage is the content in the main.js frame, loaded in by a different set of .js files. Enough text, let’s look at some code. When the webpage loads, I tried to add a simple call to the getScript function in a .js file at the index.html level which handles switching scopes. This file, newFile, has different data definitions than the previously loaded oldFile.js which was loaded in the main.html file. $.getScript(/js/newFile.js); However this doesn’t work, since newFile.js depends on a parseData() function which is in main.js. If I open firebug up, parseData is not located in the dom tab, which I assume is related to some scoping issue with the main.html and main.js file existing in a different frame. I tried to do some targeting to the correct “frame” but I don’t think I understand jQuery enough to know what is happening. $(window.parent.frames[0]).getScript(/js/newFile.js); Any suggestions? If I were to type into firebug console “parseData” it can not find it: “ReferenceError: parseData is not defined” However, if I type in window.parent.frames[1].parseData, it can find the function. Sorry about all the rambling and poor understanding of javascript. Hopefully someone can provide some assistance! Thanks

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• Flickering Image in Java?

  - by Noah Cagle

  OK so I am coding a game right now to prepair for Ludum Dare SharkJam, and I am using a new method for programming, because the last method I had crashes my PC, so this one should work. Well it does work and all, better too, but the images that I put in it flicker. Here is the whole main class (where the images are drawn) package me.NoahCagle.watermaze; import java.awt.Color; import java.awt.Graphics; import java.awt.Image; import java.awt.image.BufferedImage; import javax.swing.JFrame; import me.NoahCagle.watermaze.entity.EntityShark; import me.NoahCagle.watermaze.entity.Player; import me.NoahCagle.watermaze.input.Keys; import me.NoahCagle.watermaze.map.Map; public class Game extends JFrame { private static final long serialVersionUID = 1L; Map map = new Map(0, 0); Player player = new Player(50, 30); static EntityShark shark = new EntityShark(400, 400); public Image dbImage; public Game() { setSize(800, 600); setDefaultCloseOperation(EXIT_ON_CLOSE); setLocationRelativeTo(null); setVisible(true); setTitle("Water Maze"); setResizable(false); setBackground(Color.blue); addKeyListener(new Keys()); } public static void main(String[] args) { new Game(); Thread s = new Thread(shark); s.start(); } public void paint(Graphics g) { dbImage = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB); g.drawImage(dbImage, map.x, map.y, null); g.drawImage(player.player, player.x, player.y, this); g.drawImage(shark.shark, shark.x, shark.y, this); repaint(); } } What this code does for me is makes the Images work correctly, just flickering, alot. Can anyone help me with my issue? EDIT: I think it has something to do with where I call the repaint method in the paint method, so look there.

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• What language/framework (technology) to use for website (flash games portal)

  - by cripox

  Hello, I know there are a lot of similar questions on the net, but because I am a newbie in web development I didn't find the solution for my specific problem. I am planing on creating a flash games portal from scratch. It is a big chance that there will be big traffic from the beginning (millions of pageviews). I want to reduce the server costs as much as possible but in the same time to not be tide to an expensive contract as there is a chance that the project will not be as successfully as I want and in that case the money would be very little. The question is : what technology to use? I don't know any web dev technology yet so it doesn't matter what I will learn. My web dev experience is a little php 8 years ago, and from then I programmed in C++ / Java- game and mobile development. I like Java and C syntax and language very much and I tend to dislike dynamic typing or non robust scripting (like php)- but I can get along if these are the best choices. The candidates are now: - Grails (my best for now) Ruby on Rails Cake PHP Other technologies (Google App Engine, Python/Django etc...) I was considering at first using pure C and compiling the web app in the server- just to squeeze more from the servers, but soon I understand that this is overkill. Next my eyes came on Ruby - as there is a lot of buzz for it's easiness of use. Next I discovered Grails and looked at Java because it is said that it is "faster". But I don't know what this "Faster" really means on my needs, so here comes the first question: 1) What will be my biggest consumption on the server, other than bandwidth, for a lot of flash content requests? Is it memory? I heard that Java needs a lot of memory, but is faster. Is it CPU? I am planning to take some daily VPS.NET nodes at first, to see if there is a demand, and if the "spike" is permanent to move to a dedicated server (serverloft.com has some good offers), else to remain with less nodes. I was also considering developing in Google App Engine- cheap or free hosting to use at first - so I can test my assumption- and also very easy to use (no need for sys administration) but the costs became high if used more ( 3 million games played / month .. x mb/ each). And the issue with Google is that it looks me in this technology. My other concern is scalability (not only for traffic/users, but as adding functionality) My plans are to release a functional site in just 4 weeks (just the basics frontend and some quick basic backend - so I can be able to modify some things and add games manually) - but then to raise it and add more things to it. I am planning to take a little different approach than other portals so I need to write it from scratch (a script will not do). 2) Will Grails take much more resources than RoR or Php server wise? I heard that making it on Java stack will be hardware expensive and is overkill if you don't make a bank application. My application will not be very complex (I hope and i will try to) but will have a lot of traffic. I also took in account using CDN for files, but the cheapest CDN found was 5c/GB (vps.net) and the cost per gb on serverloft (http://www.serverloft.com/dedizierte-server/server-details.php?products=4) is only 1.79 cents/GB and comes with the other resources either. I am new to this domain (web). I am learning the ropes and searching on the web for ~half of year but don't have any really practical experience, so I know that I must have some naive thinking and other issues that i don't know from now, so please give me any advice you want regarding anything, not just the specific questions asked. And thank you so much for such great community!

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• jQuery image loop not displaying any images

  - by user1871097

  I'm trying to create a very basic image gallery in jQuery. The goal is to have 3 images fade in and out in a sequential order. So image 1 is displayed, fades to image 2 etc. then the whole thing loops again. My HTML code so far is as follows: <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> <title>Slider</title> <style type="text/css"> .slider{ width: 2848px; height: 2136px; overflow: hidden; margin: 30px auto; } .slider img{ width:2848px; height:2136px; display:none; } </style> <script src="//ajax.googleapis.com/ajax/libs/jquery/1.8.3/jquery.min.js"></script> <script src="//ajax.googleapis.com/ajax/libs/jqueryui/1.9.2/jquery-ui.min.js"></script> <script src="Slider2.js"></script> </head> <body onload="Slider2"();> <div class="slider"> <img id="1" src="31.jpg" border="0" alt="city"/> <img id="2" src="2vrtigo2.jpg" border="0" alt="roof"/> <img id="3" src="3.jpg" border="0" alt="sea"/> </div> </body> And the jQuery code looks like this: function Slider2() { var total = $(".slider img").size(); for (i=1; i<=total; i+=1) { $(".slider #"+i).fadeIn(600); $(".slider #"+i).delay(2000).hide; }} A quick syntactical note, I've also tried using i++ in the last argument of the For Loop. The result of this code is a blank, white page. I know some of the HTML is being compiled because the enormous 2848x2136 div creates scroll bars on the browser. If anyone could help me out, that would be greatly appreciated. Obviously I'm relatively new to web programming and would love some insight into why this isn't working. Thanks!

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• Objective-C vs JavaScript loop performance

  - by micadelli

  I have a PhoneGap mobile application that I need to generate an array of match combinations. In JavaScript side, the code hanged pretty soon when the array of which the combinations are generated from got a bit bigger. So, I thought I'll make a plugin to generate the combinations, passing the array of javascript objects to native side and loop it there. To my surprise the following codes executes in 150 ms (JavaScript) whereas in native side (Objective-C) it takes ~1000 ms. Does anyone know any tips for speeding up those executing times? When players exceeds 10, i.e. the length of the array of teams equals 252 it really gets slow. Those execution times mentioned above are for 10 players / 252 teams. Here's the JavaScript code: for (i = 0; i < GAME.teams.length; i += 1) { for (j = i + 1; j < GAME.teams.length; j += 1) { t1 = GAME.teams[i]; t2 = GAME.teams[j]; if ((t1.mask & t2.mask) === 0) { GAME.matches.push({ Team1: t1, Team2: t2 }); } } } ... and here's the native code: NSArray *teams = [[NSArray alloc] initWithArray: [options objectForKey:@"teams"]]; NSMutableArray *t = [[NSMutableArray alloc] init]; int mask_t1; int mask_t2; for (NSInteger i = 0; i < [teams count]; i++) { for (NSInteger j = i + 1; j < [teams count]; j++) { mask_t1 = [[[teams objectAtIndex:i] objectForKey:@"mask"] intValue]; mask_t2 = [[[teams objectAtIndex:j] objectForKey:@"mask"] intValue]; if ((mask_t1 & mask_t2) == 0) { [t insertObject:[teams objectAtIndex:i] atIndex:0]; [t insertObject:[teams objectAtIndex:j] atIndex:1]; /* NSArray *newCombination = [[NSArray alloc] initWithObjects: [teams objectAtIndex:i], [teams objectAtIndex:j], nil]; */ [combinations addObject:t]; } } } ... the array in question (GAME.teams) looks like this: { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 1; mask = 2; name = B; score = 0; } ); mask = 3; name = A; }, { count = 2; full = 1; list = ( { index = 0; mask = 1; name = A; score = 0; }, { index = 2; mask = 4; name = C; score = 0; } ); mask = 5; name = A; },

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• how to create multiple tcp connections between server and client

  - by lowcosthighperformance

  I am new in Unix/Linux networking programming, so I have written server-client program in below.In this code there is one socket between client and server, client requests to server, then server responses from 1 to 100 numbers to client. So my question is how can we do this process with 3 socket( tcp connection) without using thread? ( e.g. First socket runs then second runs then third runs then first again .. ) Do you have any suggestion? Thank you client.c int main() { int sock; struct sockaddr_in sa; int ret; char buf[1024]; int x; sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_port = htons(SERVER_PORT); inet_pton (AF_INET, SERVER_IP, &sa.sin_addr); ret = connect (sock, (const struct sockaddr *) &sa,sizeof (sa)); if (ret != 0) { printf ("connect failed\n"); exit (0); } x = 0; while (x != -1) { read (sock, buf , sizeof(int)); x = ntohl(*((int *)buf)); if (x != -1) printf ("int rcvd = %d\n", x); } close (sock); exit (0); } server.c int main() { int list_sock; int conn_sock; struct sockaddr_in sa, ca; socklen_t ca_len; char buf[1024]; int i; char ipaddrstr[IPSTRLEN]; list_sock = socket (AF_INET, SOCK_STREAM, 0); bzero (&sa, sizeof(sa)); sa.sin_family = AF_INET; sa.sin_addr.s_addr = htonl(INADDR_ANY); sa.sin_port = htons(SERVER_PORT); bind (list_sock,(struct sockaddr *) &sa,sizeof(sa)); listen (list_sock, 5); while (1){ bzero (&ca, sizeof(ca)); ca_len = sizeof(ca); // important to initialize conn_sock = accept (list_sock,(struct sockaddr *) &ca,&ca_len); printf ("connection from: ip=%s port=%d \n",inet_ntop(AF_INET, &(ca.sin_addr), ipaddrstr, IPSTRLEN),ntohs(ca.sin_port)); for (i=0; i<100; ++i){ *((int *)buf) = htonl(i+20); // we using converting to network byte order write (conn_sock, buf, sizeof(int)); } * ((int *)buf) = htonl(-1); write (conn_sock, buf, sizeof(int)); close (conn_sock); printf ("server closed connection to client\n"); } }

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• How can I find a URL called [link] inside a block of HTML containing other URLs?

  - by DrTwox

  I'm writing a script to rewrite Reddit's RSS feeds. The script needs to find a URL named [link] inside a block of HTML that contains other URLs. The HTML is contained in an XML element called <description>. Here are two examples of the <description> element from I need to parse and the [link] I would need to get. First example: <description>submitted by &lt;a href=&#34;http://www.reddit.com/user/wildlyinaccurate&#34;&gt; wildlyinaccurate &lt;/a&gt; &lt;br/&gt; &lt;a href=&#34;http://wildlyinaccurate.com/a-hackers-guide-to-git&#34;&gt;[link]&lt;/a&gt; &lt;a href="http://www.reddit.com/r/programming/comments/26jvl7/a_hackers_guide_to_git/"&gt;[66 comments]&lt;/a&gt;</description> The [link] is: http://wildlyinaccurate.com/a-hackers-guide-to-git Second example: <description>&lt;!-- SC_OFF --&gt;&lt;div class=&#34;md&#34;&gt;&lt;p&gt;I work a support role at a company where I primarily fix issues our customers our experiencing with our software, which is a browser based application written primarily in javascript. I&amp;#39;ve been doing this for 2 years, but I want to take it to the next level (with the long term goal being that I become proficient enough to call myself a developer). I&amp;#39;ve been reading &amp;quot;Javascript The Definitive Guide&amp;quot; by O&amp;#39;Reilly but I was wondering if any of you more experienced users out there had some tips on taking it to the next level. Should I start incorporating some PHP and Jquery into my learning? Side projects on my spare time? Any good online resources? Etc. &lt;/p&gt; &lt;p&gt;Thanks! &lt;/p&gt; &lt;/div&gt;&lt;!-- SC_ON --&gt; submitted by &lt;a href=&#34;http://www.reddit.com/user/56killa&#34;&gt; 56killa &lt;/a&gt; &lt;br/&gt; &lt;a href=&#34;http://www.reddit.com/r/javascript/comments/26nduc/i_want_to_become_more_experienced_with_javascript/&#34;&gt;[link]&lt;/a&gt; &lt;a href="http://www.reddit.com/r/javascript/comments/26nduc/i_want_to_become_more_experienced_with_javascript/"&gt;[4 comments]&lt;/a&gt;</description> The [link] is: http://www.reddit.com/r/javascript/comments/26nduc/i_want_to_become_more_experienced_with_javascript/

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• Database advantages? Access, MySQL, msSQL, or any others?

  - by JimZ

  Dear all Stackoverflowers, I just started to learn programming and now I'm putting this question online based on a quote: no question is silly My work needs to develop a order system based on web, which wants a database system. Since using Excel for years as a general office user, I naturally turn this to Access. However, most people say Access is very limited comparing to MySQL or MSSQL, or any other more professional database system. But after developing some functions for my company's order system, I really find Access can fulfill my request. And I also tried MSSQL to develop, which I found it not quite convenient to use. I have searched in stackoverflow and find no general answer about my doubt. Now I am sincerely hoping some experienced and professional developers could clear my doubts. Now I'm listing some Access advantages, which I don't think other database system have. I hope you could help me also find these advantages in others. 1. Access is portable, I can just copy a xxx.accdb file to my company and continue with development. 2. Access is easy to generate helpful table, for example, it will automatically generate a field that can automatically count, could be used as primary key value. 3. it is more compatable with Excel, to display and filter data. 4. importantly, it nerely needs no environment to setup, just needs MS Office to be installed. ............others However, I also find some points that MSSQL is advantaged: 1. security reasons 2. easy to backup, ( just use BACKUP..... sql statement to do it) 3. can edit stored procedure to save some functions to database ...............others specifically, I wish some friends could tell me how to make other database portable? since I usually work both at home and in office. It's a headache to move MSSQL work to my office, since the version of MSSQL is not the same. Thank you all and best regards, :)

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• Getting Frequency Components with FFT

  - by ruhig brauner

  so I was able to solv my last problem but i stubmled upon the next already. So I want to make a simple spectrogram but in oder to do so I want to understand how FFT-libaries work and what they actually calculate and return. (FFT and Signal Processing is the number 1 topic I will get into as soon as I have time but right now, I only have time for some programming exercises in the evening. ;) ) Here I just summarized the most important parts: int framesPerSecond; int samplesPerSecond; int samplesPerCycle; // right now i want to refresh the spectogram every DoubleFFT_1D fft; WAVReader audioIn; double audioL[], audioR[]; double fftL[], fftR[]; ..... framesPerSecond = 30; audioIn= new WAVReader("Strobe.wav"); int samplesPerSecond = (int)audioIn.GetSampleRate(); samplesPerCycle = (int)(audioIn.GetSampleRate()/framesPerSecond); audioL = new double[samplesPerCycle*2]; audioR = new double[samplesPerCycle*2]; fftL = new double[samplesPerCycle]; fftR = new double[samplesPerCycle]; for(int i = 0; i < samplesPerCycle; i++) { // don't even know why,... fftL[i] = 0; fftR[i] = 0; } fft = new DoubleFFT_1D(samplesPerCycle); ..... for(int i = 0; i < samplesPerCycle; i++) { audioIn.GetStereoSamples(temp); audioL[i]=temp[0]; audioR[i]=temp[1]; } fft.realForwardFull(audioL); //still stereo fft.realForwardFull(audioR); System.out.println("Check"); for(int i = 0; i < samplesPerCycle; i++) { //storing the magnitude in the fftL/R arrays fftL[i] = Math.sqrt(audioL[2*i]*audioL[2*i] + audioL[2*i+1]*audioL[2*i+1]); fftR[i] = Math.sqrt(audioR[2*i]*audioR[2*i] + audioR[2*i+1]*audioR[2*i+1]); } So the question is, if I want to know, what frequencys are in the sampled signal, how do I calculate them? (When I want to print the fftL / fftR arrays, I get some exponential formes at both ends of the array.) Thx :)

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• Type casting int into double C++

  - by user1705380

  I am new to programming and this might be an obvious question, though i cannot for life of me figure out why my program is not returning as a double. I am suppose to write a stocks program that takes in shares of stock, whole dollar portion of price and the fraction portion. And the fraction portion is to be inputted as two int values, and include a function definition with 3 int values.The function returns the price as a double. #include <iostream> using namespace std; int price(int, int, int); int main() { int dollars, numerator, denominator, price1, shares; char ans; do { cout<<"Enter the stock price and the number of shares.\n"; cout<<"Enter the price and integers: Dollars, numerator, denominator\n"; cin>>dollars>>numerator>>denominator; cout<<"Enter the number of shares held\n"; cin>>shares; cout<<shares; price1 = price(dollars,numerator,denominator); cout<<" shares of stock with market price of "; cout<< dollars << " " << numerator<<'/'<<denominator<<endl; cout<<"have a value of " << shares * price1<<endl; cout<<"Enter either Y/y to continue"; cin>>ans; }while (ans == 'Y' || ans == 'y'); system("pause"); return 0; } int price(int dollars, int numerator, int denominator) { return dollars + numerator/static_cast<double>(denominator); }

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• Does this type of function or technique have a name?

  - by DHR

  HI there, I'm slightly new to programming, more of a hobby. I am wondering if a the following logic or technique has a specific name, or term. My current project has 7 check boxes, one for each day of the week. I needed an easy to save which boxes were checked. The following is the method to saved the checked boxes to a single number. Each checkbox gets a value that is double from the last check box. When I want to find out which boxes are checked, I work backwards, and see how many times I can divide the total value by the checkbox value. private int SetSelectedDays() { int selectedDays = 0; selectedDays += (dayMon.Checked) ? 1 : 0; selectedDays += (dayTue.Checked) ? 2 : 0; selectedDays += (dayWed.Checked) ? 4 : 0; selectedDays += (dayThu.Checked) ? 8 : 0; selectedDays += (dayFri.Checked) ? 16 : 0; selectedDays += (daySat.Checked) ? 32 : 0; selectedDays += (daySun.Checked) ? 64 : 0; return selectedDays; } private void SelectedDays(int n) { if ((n / 64 >= 1) & !(n / 64 >= 2)) { n -= 64; daySun.Checked = true; } if ((n / 32 >= 1) & !(n / 32 >= 2)) { n -= 32; daySat.Checked = true; } if ((n / 16 >= 1) & !(n / 16 >= 2)) { n -= 16; dayFri.Checked = true; } if ((n / 8 >= 1) & !(n / 8 >= 2)) { n -= 8; dayThu.Checked = true; } if ((n / 4 >= 1) & !(n / 4 >= 2)) { n -= 4; dayWed.Checked = true; } if ((n / 2 >= 1) & !(n / 2 >= 2)) { n -= 2; dayTue.Checked = true; } if ((n / 1 >= 1) & !(n / 1 >= 2)) { n -= 1; dayMon.Checked = true; } if (n > 0) { //log event } } The method works well for what I need it for, however, if you do see another way of doing this, or a better way to writing, I would be interested in your suggestions.

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• Need advice about pointers and time elapsed program. How to fix invalid operands and cannot convert errors?

  - by user1781382

  I am trying to write a program that tells the difference between the two times the user inputs. I am not sure how to go about this. I get the errors : Line 27|error: invalid operands of types 'int' and 'const MyTime*' to binary 'operator-'| Line |39|error: cannot convert 'MyTime' to 'const MyTime*' for argument '1' to 'int DetermineElapsedTime(const MyTime*, const MyTime*)'| I also need a lot of help in this problem. I don't have a good curriculum, and my class textbook is like cliffnotes for programming. This will be my last class at this university. The C++ teztbook I use(my own not for class) is Sam's C++ One hour a day. #include <iostream> #include<cstdlib> #include<cstring> using namespace std; struct MyTime { int hours, minutes, seconds; }; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2); long t1, t2; int DetermineElapsedTime(const MyTime *t1, const MyTime *t2) { return((int)t2-t1); } int main(void) { char delim1, delim2; MyTime tm, tm2; cout << "Input two formats for the time. Separate each with a space. Ex: hr:min:sec\n"; cin >> tm.hours >> delim1 >> tm.minutes >> delim2 >> tm.seconds; cin >> tm2.hours >> delim1 >> tm2.minutes >> delim2 >> tm2.seconds; DetermineElapsedTime(tm, tm2); return 0; } I have to fix the errors first. Anyone have any ideas??

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