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---需要了解cstring和string之间的区别</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. 因为数组下标是从0开始的.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循环体前声明运行慢，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;}