strstr()的实现

#include<iostream>
#include<stdio.h>

int my_strstr(const char *src,const char *des);
int  my_strstr(const char *src,const char *des)
{
if(NULL == src || NULL == des)
return -1;

const char *p_src = NULL;
const char *p_des = NULL;
int i = 0 ;

for(p_src = src; *p_src != '\0';p_src++)
{
int flag = 0;
if(*p_src == *p_src)
{

int j ;
for(p_des = des,j = 0 ;*p_des != '\0';p_des++)
{
if(*p_des == *p_src)
{
flag = 1;
j++;
p_src++;
}else
{   p_src = p_src-j;
flag = 0;
break;
}

}
if(flag == 1)
{
printf("find !\n");
return i;
}

}

i++;
}
printf("not find !\n");
return -1;

}
int main()
{
char src[] = "liusenlin";
char des[] = "sen";

int psition = 0;
psition = my_strstr(src,des);
printf("%d \n",psition);

char des1[] = "lsl";
int psition1 = 0;
psition1 = my_strstr(src,des1);
printf("%d\n",psition1);
return 0;
}