判断后一个字符串是否是前一个字符串的子串？帮忙填空

#include<stdio.h>
#include<string.h>
#include<malloc.h>
void main()
{
    char *p1, *p2;
    int i, j, n = 0, leng;
    p1 = (char *)malloc(100);
    p2 = (char *)malloc(100);
    scanf("%s%s", p1, p2);
    printf("%s\t%s\n", p1, p2);
    while (*p1 != *p2 && *p1 != '\0')
        --------;

    leng = strlen(p2);
    while (*p2 != '\0' && *p1 != '\0')
    {
        if (*p1 == *p2)
            ----------;
        p1++;
        p2++;
    }
    printf("n=%d  leng=%d\n", n, leng);
    if (--------------)
        printf("yes\n");
    else
        printf("no\n");
    free(p1);free(p2);

}

void main()
{
    char *p1, *p2;
    int i, j, n = 0, leng;
    p1 = (char *)malloc(100);
    p2 = (char *)malloc(100);
    scanf("%s%s", p1, p2);
    printf("%s\t%s\n", p1, p2);
    while (*p1 != *p2 && *p1 != '\0')
        p1++--------;

    leng = strlen(p2);
    while (*p2 != '\0' && *p1 != '\0')
    {
        if (*p1 == *p2)
            ++n----------;
        p1++;
        p2++;
    }
    printf("n=%d  leng=%d\n", n, leng);
    if (n==leng--------------)
        printf("yes\n");
    else
        printf("no\n");
    free(p1);free(p2);

}

#include "stdio.h"
#include "string.h"
#include "stdlib.h"
void main()
{
    char *p1, *p2,*p11,*p22;
    int n = 0, leng;
    p1 = (char *)malloc(100);
    p2 = (char *)malloc(100);
    p11=p1;
    p22=p2;
    scanf("%s%s", p1, p2);
    printf("%s\n%s\n", p1, p2);
    while (*p1 != *p2 && *p1 != '\0')
        p1++;

    leng = strlen(p2);
    while (*p2 != '\0' && *p1 != '\0')
    {
        if (*p1 == *p2)
            ++n;
        p1++;
        p2++;
    }
    printf("n=%d,leng=%d\n", n, leng);
    if (n==leng)
        printf("yes\n");
    else
        printf("no\n");
    free(p11);
    free(p22);
    system("pause");
}
你那个程序有点问题，最后free有点问题，改了一下，似乎ok了^_^

kmp算法！

i和j似乎没有用上  这个是研究生考试题  而且这样调试出来的程序要是主串中有重复的字符串就会出错

对头，找个程序很不完善，只能对付简单点的
第一次出现不完整的，后面出现完整的字符串就无法实现功能了
呵呵