C++关注备注部分知识点

//关注备注部分知识点。

#include <iostream>
#include <string><span style="white-space:pre">	</span><span style="color:#cc0000;">//1---须要了解cstring和string之间的差别</span>
int main()
{
using namespace std;
cout<<"Please Enter a string:\n";
string word;
cin>>word;//
//	char temp;<span style="white-space:pre">	</span><span style="color:#cc0000;">//3---</span>
int i,j;
//<span style="white-space:pre">	</span>for(i=0,j=word.size()-1;i<=j;++i,--j)
<span style="white-space:pre">	</span>for(i=0,j=word.length()-1;i<=j;++i,--j)
<span style="color:#ff0000;">//2---word.size() word应该是个数组. <span style="font-family: Arial, Helvetica, sans-serif;">word.length()和</span><span style="font-family: Arial, Helvetica, sans-serif;"> word.size() 则表示数组的长度. 由于数组下标是从0開始的.所以 要-1 防止下标越界</span></span>
{
char temp;//内部声明temp在每次循环存在被分配和释放，相对for循环体前声明执行慢，循环结束即会释放
//		char temp=word[i];<span style="font-family: Arial, Helvetica, sans-serif;">	</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="color:#ff0000;">//3--</span>-</span>
//		char temp=word[i];<span style="font-family: Arial, Helvetica, sans-serif;">	</span><span style="font-family: Arial, Helvetica, sans-serif;"><span style="color:#ff0000;">//3---</span></span>
temp=word[i];
word[i]=word[j];
word[j]=temp;
}
cout<<word<<endl;

return 0;
}