[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

 1 #include <iostream>
 2 using namespace std;
 3
 4 int main(){
 5     int sum = 0;
 6     int n = 5;
 7     for(int i = 0 ; i < n ; i++){
 8         sum += i;
 9     }
10     cout << i << endl;
11 }

报错

 1 #include <iostream>
 2 using namespace std;
 3
 4 int main(){
 5     int sum = 0;
 6     int n = 5;
 7     int i;
 8     for(i = 0 ; i < n ; i++){
 9         sum += i;
10     }
11     cout << i << endl;
12 }

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