strstr 函数的实现

#include <stdio.h>

const char *my_strstr(const char *str, const char *sub_str)
{
    for(int i = 0; str[i] != ‘\0‘; i++)
    {
        int tem = i; //tem保留主串中的起始判断下标位置 
        int j = 0;
        while(str[i++] == sub_str[j++])
        {
            if(sub_str[j] == ‘\0‘)
            {
                return &str[tem];
            }
        }
        i = tem;
    }

    return NULL;
}

int main()
{
    char *s = "1233345hello";
    char *sub = "345";
    printf("%s\n", my_strstr(s, sub));
    return 0;
}