day 7

定义两个字符指针，分配指向堆区空间，实现字符串比较，释放
 

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int cmp(char *p1,char *p2)
{
	while(*p1==*p2&&*p1!='\0'&&*p2!='\0')
	{
		p1++;
		p2++;
	}
	int num=*p1-*p2;
	if(num<0)
	{
		printf("p1<p2\n");
	}
	else if(num>0)
	{
		printf("p1>p2\n");
	}
	else
	{
		printf("p1==p2\n");
	}
	return num;
}

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

	char *p1=(char *)malloc(sizeof(char)*10);
	char *p2=(char *)malloc(sizeof(char)*10);
	int n=0;
	printf("输入p1:\n");
	gets(p1);
	printf("输入p2：\n");
	gets(p2);
	printf("%d\n",cmp(p1,p2));
	free(p1);
	free(p2);
	p1=NULL;
	p2=NULL;
	return 0;
}