实验11-1-8 查找子串

#include <stdio.h>
#define MAXS 30

char *search(char *s, char *t);
void ReadString( char s[] ); /* 裁判提供，细节不表 */

int main()
{
    char s[MAXS], t[MAXS], *pos;

    ReadString(s);
    ReadString(t);
    pos = search(s, t);
    if ( pos != NULL )
        printf("%d
", pos - s);
    else
        printf("-1
");

    return 0;
}

/* 你的代码将被嵌在这里 */
char *search(char *s, char *t)
{
    
    int len = 0, i;
    char *p, *ret;
    
    p = t;
    while (*p != '')
    {
        len++;
        p++;
    }
    
    p = s;
    while (*p != '')
    {
        for (i = 0; i < len; i++)
        {
            if (p[i] != t[i])
            {
                break;
            }
        }
        if (i == len)
        {
            break;
        }
        p++;
    }
    if (*p != '')
    {
        ret = p;
    }
    else
    {
        ret = NULL;
    }
    
    return ret;
}