Question

I found this code snippet here, but I just can’t figure out what the variables cSrt and result are!

for(int i = 0; i<1000000; i++){
    CC_MD5(cStr, strlen(cStr), result);
    sprintf(cStr, "%02x%02x", result[0], result[1]);
}

The compiler is telling me that they are char and unsigned char, but when I try to run it, it gives me an EXC_BAD_ACCESS at the sprintf-line.

Have you got any idea what I can do to make this snippet work? Thanks.

Answer 1

cStr and result should be arrays of (unsigned) chars, or pointers to (unsigned) char buffers.

For example

char cStr[] = "This is my str";
char result[16];
for( int i=0; i<1000000; i++ )
{
    CC_MD5( cStr, strlen(cStr), result );
    sprintf(cStr, "%02x%02x", result[0], result[1]);
}

Note that cStr may be const, since it is only read, but result should be non-constant buffer, because CC_MD5 writes the result there.

Edit:

Actually, in this case, cStr cannot be const, as you write to it in the sprintf line, but as far as you only use it in CC_MD5 it should be OK.