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hex converting

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  • D David Crow

    Ok, numbers are treated differently when sending them versus displaying them. When you talk about a "hex number," that is for display purposes only. In other words, 1609564729 and 0x5FF00239 are treated identically by the computer. It stores them as binary regardless of how you use them. Now if you are sending "1609564729" and "0x5FF00239" (notice the quotes) to some other process/computer, then they are two totally different things. So, whether you send 1609564729 or 0x5FF00239 to the server, it makes no difference. What mechanism are you using to send data to the server?

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    NewHSKid
    wrote on last edited by
    #9

    Hi, thanks for helping me. mechanism? I want to use the int send command. Is that what you are talking about. So you are saying that I can use a int variable, but just put 0x in front of the number?

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    • N NewHSKid

      That is what I want to do later on, I want to program video games. :-) Can you explain what the char message[32]does?

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      David Crow
      wrote on last edited by
      #10

      It reserves a spot (named "message") in memory for 32 characters.

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      • D David Crow

        It reserves a spot (named "message") in memory for 32 characters.

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        NewHSKid
        wrote on last edited by
        #11

        but I only need 4 bytes? should i change the 32 to 4 then? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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        • N NewHSKid

          Hi, thanks for helping me. mechanism? I want to use the int send command. Is that what you are talking about. So you are saying that I can use a int variable, but just put 0x in front of the number?

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          David Crow
          wrote on last edited by
          #12

          Bingo!! These three code snippets are the same: int num = 123456789; // base-10 SendToServer(num); int num = 0x75BCD15; // base-16 SendToServer(num); int num = 0726746425; // base-8 SendToServer(num);

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          • N NewHSKid

            but I only need 4 bytes? should i change the 32 to 4 then? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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            David Crow
            wrote on last edited by
            #13

            You don't need this at all. Dangleberry's post was just showing you how to convert a number to a string (which was then displayed in a message box).

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            • D David Crow

              Bingo!! These three code snippets are the same: int num = 123456789; // base-10 SendToServer(num); int num = 0x75BCD15; // base-16 SendToServer(num); int num = 0726746425; // base-8 SendToServer(num);

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              NewHSKid
              wrote on last edited by
              #14

              For the send command, i have problems it needs the socket and a message and a length, and some flags. Its says I can't use int because the message has to be const char *. for the length is that in bytes? should it be 4 or 10 to represent all numbers/letters? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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              • N NewHSKid

                For the send command, i have problems it needs the socket and a message and a length, and some flags. Its says I can't use int because the message has to be const char *. for the length is that in bytes? should it be 4 or 10 to represent all numbers/letters? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                David Crow
                wrote on last edited by
                #15

                How about a code snippet of what you are trying to do?

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                • D David Crow

                  How about a code snippet of what you are trying to do?

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                  NewHSKid
                  wrote on last edited by
                  #16

                  hi, here is what i want to do, the program is connected to the server already. (I don't know how to connect, i just use my friends dad program to connect) int message; message = 0x5FF0023A; send(s, message, strlen(message), 0); It says send can't convert parameter 2 from int to const char * and it says the same thing about strlen. Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                  • N NewHSKid

                    hi, here is what i want to do, the program is connected to the server already. (I don't know how to connect, i just use my friends dad program to connect) int message; message = 0x5FF0023A; send(s, message, strlen(message), 0); It says send can't convert parameter 2 from int to const char * and it says the same thing about strlen. Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                    David Crow
                    wrote on last edited by
                    #17

                    NewHSKid wrote: the program is connected to the server already. (I don't know how to connect, i just use my friends dad program to connect) Does that mean he is supplying you with a valid socket descriptor? Given that the second parameter of send() is expecting a char*, you'll need:

                    int nMessage = 0x5FF0023A;
                    char szMessage[9]; // hold 8 characters plus a \0
                    sprintf(szMessage, "%d", nMessage); // or itoa(nMessage, szMessage, 16);
                    int nBytes = send(s, szMessage, lstrlen(szMessage), 0);

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                    • D David Crow

                      NewHSKid wrote: the program is connected to the server already. (I don't know how to connect, i just use my friends dad program to connect) Does that mean he is supplying you with a valid socket descriptor? Given that the second parameter of send() is expecting a char*, you'll need:

                      int nMessage = 0x5FF0023A;
                      char szMessage[9]; // hold 8 characters plus a \0
                      sprintf(szMessage, "%d", nMessage); // or itoa(nMessage, szMessage, 16);
                      int nBytes = send(s, szMessage, lstrlen(szMessage), 0);

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                      NewHSKid
                      wrote on last edited by
                      #18

                      Hi, Thanks for helping. So when i use that code, the receiving program will get the hex number of 5FF0023A? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                      • N NewHSKid

                        hi, here is what i want to do, the program is connected to the server already. (I don't know how to connect, i just use my friends dad program to connect) int message; message = 0x5FF0023A; send(s, message, strlen(message), 0); It says send can't convert parameter 2 from int to const char * and it says the same thing about strlen. Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                        Lost User
                        wrote on last edited by
                        #19

                        try this : send(s, (const char FAR*)message, sizeof(message), 0); though the sizeof(message) param can just be 0, as message oriented sockets will send a zero-length transport datagram. :cool:

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                        • N NewHSKid

                          Hi, Thanks for helping. So when i use that code, the receiving program will get the hex number of 5FF0023A? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                          David Crow
                          wrote on last edited by
                          #20

                          No, the recv() function on the other end will receive "5FF0023A" as a char*. It can convert that to an integer (long actually) with strtol(). long lMessage; char szMessage[9], *stop; int nBytes = recv(s, szMessage, sizeof(szMessage), 0); lMessage = strtol(szMessage, &stop, 16);

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                          • N NewHSKid

                            My friends dad gave me a program to write cause he said it will make me learn. I have to connect to a server and send it 4 byte messages that have the form of 5FF00239. The message changes though, because the window (dialog i think its called) has 2 check boxes. If only the first check box is checked then the message should be 5FF00239 and if the second check box is only check it should be 5FF0023A. But if both are checked then he wants the message to be 5FF0023B. How do I make these messages? I don't know what type they should be. I can do everything else he wants except i don't know how to do the message. I thought it would be a string, but he says if it is, then the message is 8 bytes instead of 4? Please help me...

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                            Ken Mazaika
                            wrote on last edited by
                            #21

                            Windows Sockets can be highly complicated as well as windows programming for people somewhat new to programming. From your posts it seems as if your skipping quite a few steps in the learning process. I think if you ended up writing a program that does what you want now it will be mostly cut/paste code and you won't get much out of the experience. This program would be an excellent learning experience, but you should make creating it more of a long range goal.

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                            • N NewHSKid

                              but I only need 4 bytes? should i change the 32 to 4 then? Jimmy Just cause I am 15, doesn't mean I'm dumb! (I'll really be 4 on Feb. 29...the year 2004)

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                              Terry ONolley
                              wrote on last edited by
                              #22

                              The only actual "numbers" in the computer are semi-conductor gates that are either on or off. That is fine for the computer, but most people need something visual to help us understand what is going on. To the computer, all numbering base sytems look the same - binary. It is only when outputting the graphical representation of those numbers that you need to worry about data types and base. So, the number 255 is represented in the coputer by 8 logic gates being on: 11111111 If you, the human, wants to see that number in hexadecimal, then you tell your program to format that number in base 16 and you see "FF". Now, the characters "FF" are represented by the ascii code for the letter 'F' - which is 70 or x40 - so if you looked at the raw bits for the characters "FF" you would see 70 70 or the bits 01000110, 01000110. So what happened??? You started with 11111111 and ended up with 01000110, 01000110! The confusion comes from figuring out what format the reciever of the data is expecting. That is what function headers are for. They define how to interperet the bits that are being sent.



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