举例说明strcmp的用法

strcmp为比较字符串函数（只能比较字符串的大小）
strcmp函数的原型为：int strcmp( const char *string1, const char *string2 );
返回值为：
Value Relationship of string1 to string2
< 0 string1 less than string2 （string1 < string2）
0 string1 identical to string2 （string1 = string2）
> 0 string1 greater than string2 （string1 > string2）

eg:

#define	_CRT_SECURE_NO_WARNINGS
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
int main()
{
	//字符串比较
	char arr1[] = "AbCd";
	char arr2[] = "abcd";
	char arr3[] = "AbCd";
	char arr4[] = "ABCD";
	printf("%d\n", strcmp(arr1, arr2));
	printf("%d\n", strcmp(arr1, arr3));
	printf("%d\n", strcmp(arr1, arr4));
	system("pause");
	return 0;
}
输出结果为：

因此 arr1 < arr2 ; arr1 = arr3 ; arr1 > arr4