学步园

//倒置字符串
#include <iostream>
using namespace std;

//倒置原字符串
void reverse1(char * s)
{
	if (s)
	{
		char temp;
		char * end=s;
		while (*end)//记住这里end只表示一个字符
		{
			end++;
		}
		--end;
		while (s<end)
		{
			temp =*s;
			*s++=*end;
			*end-- =temp;
		}
	}
}
//返回个倒置字符串，不改变原字符串
char* reverse2(char * s,int m)
{
	if(s)
	{
		char *temp =new char[m+1];//没有delete以后再看吧
		//char temp[m+1]="0";
		for (auto i =0;i<m;i++)
		{
			temp[i] = s[m-i-1];
		}
		temp[m] ='\0';
		return temp;
	}
	return s;
}
//倒着显示字符串
//递归
void show(char *s)
{
	char temp;
	if(*s)
	{
		temp =*s++;
		show(s);
		cout<<temp;
	}
}
//不递归 用栈做  原理一样
void main()
{
	char s[11] ="1234567890";
	show(s);
	cout<<endl<<s<<endl;
	char *s1 =reverse2(s,strlen(s));
	for (auto i =0;i<10;i++)
	{
		cout<<*s1++;
	}
	cout<<endl;
	reverse1(s);
	cout<<s<<endl;
	system("pause");
}