C言語面接問題-文字列挿入

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


void insert(char *s,char *t, int i)
{
    char *q = t;
    char *p = s;
    if (q == NULL) return ;
    while(*p!='\0') {
        if ( 0 >= --i ) {
           printf("memove
");
           memmove(p+strlen(t),p,strlen(p));
           break;
        } 
            p++;
    }
    while(*q!=0) {
        *p=*q;
        p++;q++;
    }
}

int main(void) {
    char a[100]="Hewwwllo";
    char b[10]="abc";
    insert(a,b,5);
    printf("%s
",a);
}