博客

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

char* my_strstr(char* src , char* dest)
{
    char* fsrc = src;   //用作于循环遍历的指针
    char* rsrc = src;   //记录每次相同的首地址

    char* tdest = dest;    //用于回滚
    while (*fsrc)
    {
        rsrc = fsrc;
        while(*fsrc == *tdest && *fsrc != '\0')
        {
            fsrc++;
            tdest++;
        }
        if(*tdest == '\0')
        {
            return rsrc;
        }
        //回滚
        fsrc = rsrc;
        tdest = dest;
        fsrc++;
    }

    return NULL;
}


int main()
{
    char src[] = "hello world";
    char dest[] = "llo";

    char* p = my_strstr(src, dest);
    printf("%s\n",p);
    return EXIT_SUCCESS;
}