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Is there a way to copy a whole smaller array into a section of a larger array? For example, if I have an array of 4 characters, and an array of 16, can I copy the 4 characters into the first 4 of the array of 16. Then another 4 characters to 4-7, etc. I know it's possible to do with a loop, but I was wondering if there was a way to do it otherwise. Here's the section of code that I'm trying to get to work.

int numtype = htons(5);
char type[4] = "";
_itoa_s(numtype, type, 4, 10);
message[0] = *type;

I need to convert the message to be sent byte by byte to a server with each 4 bytes containing control messages for the server. This is just one of the 4 of 16 bytes of the whole message.

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Last Post by Ancient Dragon
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Thanks Ancient Dragon,
That seemed to get rid of my runtime errors, but it still doesn't seem to be filling the array with the correct values. Could you take a look at how I'm doing it and tell me how it could be corrected?

int numtype = htons(5);
char type[sizeof(int)];
memcpy(type, (char *)&numtype, sizeof(int));
message[0] = *type;

int numseq = htons(sequence);
har seq[sizeof(int)];
memcpy(seq, (char *)&numseq, sizeof(int));
message[4] = *seq;

int nump1 = htons(0);
char p1[sizeof(int)];
memcpy(p1, (char *)&nump1, sizeof(int));
message[8] = *p1;

int nump2 = htons(0);
char p2[sizeof(int)];
memcpy(p2, (char *)&nump2, sizeof(int));
message[12] = *p2;

I should note the message is declared as char message[16] elsewhere in the program, and sequence is just a 4 digit number.

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>>message[0] = *type;
how is message declared ? is it a character array ? Yes, then the above only copies the first byte to message. Why just memcpy to message instead of using a temporary array.

memcpy(message, (char *)&number, sizeof(int));
memcpy(&message[sizeof(int)], (char *)anotherNimber, sizeof(int));
// etc
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Doing your previous example, I would still need to go through each index in the array, wouldn't I? Unless I'm just misunderstanding. What I ultimately want to do is take 4 bytes and put them in 0-3, 4 more bytes and put them in 4-7, then 8-11, then 12-15. Is the only way to do this byte by byte with memcpy or setting up a for loop?

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>>Is the only way to do this byte by byte with memcpy or setting up a for loop?
There is one other way that I can think of *(int *)&message[0] = number;

int main()
{
    unsigned char message[4];
    int number = 1234;
    *(int *)&message[0] = number;
    cout << *(int *)message << "\n";
    return 0;
}
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