实现strstr函数

#include <iostream>using namespace std;char* strstr(char* str1,char* str2,int len1,int len2){for(int i = 0;i<len1;i++) {if(str1[i] == str2[0]){for(int j=i+1,int k=1;j<len1 && k < len2;j++,k++) {if(str1[j] != str2[k])break;else if(k == len2-1)return str1+i;}}}return NULL;}int main(){char str[] = "abcdefghijk";char* s1 = strstr(str,"ij",strlen(str),strlen("ij"));char* s2 = strstr(str,"ij");cout<<(s1 == s2 ? "true":"false")<<endl<<s1<<endl;return 0;}