Difference in uses between malloc and calloc

Question

gcc 4.5.1 c89

I have written this source code for my better understanding of malloc and calloc.

I understand, but just have a few questions

Answer 1

Look at an implementation of calloc to see the differences. It's probably something like this:

// SIZE_MAX is defined in stdint.h from C99
void *calloc( size_t N, size_t S)
{
    void *ret;
    size_t NBYTES;

    // check for overflow of size_t type
    if (N > SIZE_MAX / S) return NULL;

    NBYTES = N * S;
    ret = malloc( NBYTES);
    if (ret != NULL)
    {
        memset( ret, 0, NBYTES);
    }

    return ret;
}