C ++声明变量两次

Question

Hello everyone I am learning about the declaration of variables in C++.

Now please tell me my mistake here. Why is it bad to declare your variable twice?

int fly = 0;

for(int fly = 0; fly < 10; fly++) {
    cout << "This is a kite flying" << fly << endl:
}

Answer 1

These are two seperate variable because they are declared in a different scope . The scope of a variable is the "area" of code in which it's visible.

As a simple rule of thumb, any place where curly brackets are, or could be placed, is a new scope. The fly inside the for loop, overrides the other fly variable. If it wasn't declared, or declared under a different name. The original variable would still be accessible.