stcmp函数的实现

*/

#include <stdio.h>
#include <stdlib.h>

int  mystcmp ( const char * str1,const char* str2){
  

	int  ret  = 0;
	while ( !( ret =  *(unsigned *)str1- *(unsigned *)str2 ) && *str2  ){/* 如果字符相等循环 且str2 不等于空字符循环*/
		++str2;
		++str1;
	}
	if (ret <0)
		return -1;
	else if(ret >0)
		return  1;

	return  ret;

}

void  main (){ 
	/*  数组名 是常量指针 不能作为 变量 进行赋值*/

	char str[10]  ="123456";
	char str1[10] ="123456";
	char str2[10] = "12";
	char str3[10] = "1266";

	int test = mystcmp(str,str1);
	int  test1 = mystcmp (str1,str2);
	int  test2 = mystcmp (str2,str3);
	printf ("%d \n  %d\n  %d \n ",test,test1,test2);
	system("pause");
}