171021 c++中++i与i++的区别

c++中++i与i++的区别是什么
c++中的++i和i++

// ConsoleApplication1.cpp : 定义控制台应用程序的入口点。// c++中++i与i++的区别#include "stdafx.h"#include<iostream>  using namespace std;int main(){int i1 = 7;int a = i1++; //先赋值，再自加cout << "a =  " << a << " i1 = " << i1<<endl;int i2 = 7;int b = ++i2; //先自加，再赋值cout << "b =  " << b << " i2 = " << i2<<endl;return 0;   }

运行结果
a = 7 i1 = 8
a = 8 i2 = 8

int i = 0;  int c = (++i)+(i++)+(++i)+(i++);  cout << "c = "<<c<< " i = "<<"i" <<endl;

运行结果
c = 8 i = 4
分析
两次++i使得i的值变为2，故此 c = 2+2+2+2=8，i++在此处即为i=2
在赋值c后，两次i++使得i的结果再加2，故最终为4