具有与外部循环相同的变量名的内部循环 [英] inner loop with same variable name as outer loop

问题描述

假设以下简单代码:

for(int i=0; i < 1000; i++)
{
  cout << "Outer i: " << i << endl;
  for(int i=0; i < 12; i++)
  {
    cout << "Inner i:" << i << endl;
  }
}

效果非常好.在两个循环中使用相同的变量名，并且输出很好.

Works very nice. The same variable name in both loops used and the output is fine.

我是否正确地理解两个变量都是在堆栈上创建的，并且当外循环进入新的内循环时，会创建一个新的命名空间"(也许是错误的名称..)吗?但是为什么它会被覆盖呢?如果在内部循环中为变量选择另一个名称，我也可以从外部循环访问i.

Do I understand it right that both variables are created on stack, and when the outer loop comes to the new inner loop, a new "namespace" (maybe the wrong name..) is created? But why is it overwritten? If I choose another name for the variable in inner loop I can also access the i from outer loop.

我有点困惑.

推荐答案

命名空间"有点接近..但是它更多地是关于范围的.内层i 隐藏/抑制外层i.您可能会想到另一个示例:

"Namespace" is kinda close.. but it is more about scope. The inner i hides/surpresses the outer i. You could think of another example:

{ 
 int i=0; //outer scope i.
 {
   int i =0; //this hides the outer scope i.. I can't use outer i here

 }
  i =1 ; //inner i is out of scope.. outer i is set to 1
}

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