实现memcpy函数

#include <stdio.h>
#define N 20

void *memcpy1(void *dest, const void *src, size_t num) {
    const char *s = (char *) src;
    char *t = (char *) dest;

    while(num--)
        *t++ = *s++;

    return dest;
}

void *memcpy2(void *dest, const void *src, size_t num) {
    const void *s = src;
    void *t = dest;

    while(num--)
        *(char *)t++ = *(char *)s++;

    return dest;
}

void myprint(char *arr) {
    int i;
    for(i = 0; i < N; i++)
                printf("%c",arr[i]);
        printf("\n");
}

int main () {
    char a[N], b[N];
    int i;

    for(i = 0; i < N; i++) {
        a[i] = i + 'a';
        b[i] = '0';
    }

    myprint(b);
    memcpy2(b,a,N);
    myprint(b);


    return 0;
}