[bug] C++：[Error] name lookup of 'i' changed for ISO '

错误原因：变量i只在for循环中可见，若在循环外使用需要单独定义

#include <iostream>
using namespace std;

int main(){
    int sum = 0;
    int n = 5;
    for(int i = 0 ; i < n ; i++){
        sum += i;
    }
    cout << i << endl;
}

报错

#include <iostream>
using namespace std;

int main(){
    int sum = 0;
    int n = 5;
    int i;
    for(i = 0 ; i < n ; i++){
        sum += i;
    }
    cout << i << endl;
}

正常运行

 

参考：

https://www.cnblogs.com/expedition/p/11441388.html

https://wenda.so.com/q/1449244894722638?src=9999&cid-pre=1000204