compare two string

#include <iostream>using namespace std;//compare two stringint strcmp(char * p1, char* p2){while (p1 != '\0' && p2 != '\0' && *p1 == *p2 ){++p1;++p2;}if (*p1 == '\0' && *p2 == '\0'){return 0;}if (*p1 == '\0'){return -1;}if (*p2 == '\0'){return 1;}return *p1 - *p2;}int main(void){char a1[] = "hello";char a2[] = "hi";char a3[] = "he";cout<<strlen(a1);cout<<strlen(a2);int diff = strcmp(a1, a2);cout<<diff<<endl;diff = strcmp(a1, a3);cout<<diff<<endl;system("pause");return 0;}