#include <stdio.h>

 int my_strcmp(const char *str1,const char *str2)

 {

     //判断两个字符串是否为空

     if((str1 == NULL) && (str2 == NULL))

     {

         exit();

     }

     //利用while循环,str1不为零，判定str1的值是否等于str2的值

     while((*str1) && ((*str1==*str2)))

     {

         str1++;

         str2++;

     }

     //如果str1大于str2,第一字符串大于第二个字符串

     if(*(unsigned char *)str1 > *(unsigned char *)str2)

     {

         printf("The first string is greater than the second string\n");

         return ;

     }

     //如果str1小于str2，第一个字符串小于第二个字符串

     else if(*(unsigned char *)str1 < *(unsigned char *)str2)

     {

         printf("The first string is less than the second string\n");

         return -;

     }

     //如果循环完成，str1等于str2，那么这两个字符串相等

     else

     {

         printf("Two strings are equal\n");

         return ;

     }

 }

 int main(int argc, char *argv[])

 {

     char a[]="hfllo45";

     char b[]="hello45";

     my_strcmp(a,b);

     return ;

 }