What is the result of an initialization in C++?

Question

What is the return value of an initialization? For example: In the following code;

#include<iostream>

int main()
{
    int age = 30;          //does this statement return (thus; yield) anything?

    while(int i = 0){      //a similar statement (expression) used here in this condition
        std::cout<<"OK";   
    }

    return 0;
}

• What does the statement int age = 27; return?
• Does the usual assignment operator meaning apply when there is an initialization, where the left operand of the assignment operator is returned?

The reason why I want to know this is that, when we take a look at the conditional statement above we see a similar initialization of a variable that is used as the condition. I know that whatever value that is returned is converted to the bool type though.

Note: I am not trying to compare i to 0 in the condition of the while statement.

Answer 1

A declaration statement with an initializer is a just a declaration statement, not an expression. It does not yield a value. You can't do something like int x = (int n = 42);.

The while loop is something of a special case. You can use a declaration as the condition of a while loop. According to cppreference.com,

If this is a declaration, the initializer is evaluated before each iteration, and if the value of the declared variable converts to false, the loop is exited.