#include <string.h>
#include <stdio.h>

int main()
{
    char tab[] = "qwertyuiopasdfghjklzxcvbnm";
    char* ptr_src = tab;
    char* ptr_dst = tab + 1;
    size_t sz = 5;
    memmove(ptr_dst, ptr_src, sz);
    printf(tab);
    return 0;
}

qqwertuiopasdfghjklzxcvbnm