#include<stdio.h>
#include<assert.h>

char *Mystrcat(char *des,const char *src)
{
	assert(des != NULL && src != NULL);
	char *p = des;
	while(*des != '\0') //判断des的'\0'
	{
		des++;    //在没有找到des的'\0'时，des++来寻找des的’\0’
	}
	while(*des++ = *src++); //复制

	return p;
}

int main()
{
	//Mystrcat("abcd","xyz");//error1.写错误
	//char str1[10] = "hello";
	//Mystrcat(str1,"world");  //error2.越界
	char str1[100] = "hello ";
	Mystrcat(str1,"world");
	printf("%s\n",str1);

	//error1.写错误:试图修改字符串常量的值[字符串常量不可改]
	//error2.字符串越界（危险！）：定义str1[100],当定义str[10]时，内存不够程序崩溃！

	return 0;
}