What exactly is a return value?

Answer 1

Could you please explain a bit clearer

Answer 2

Something returned from functions. For example, define a function:

int a_function()
{
return 42;
}

Then,

int number = a_function();

number will be 42 because a_function() returns 42.

Answer 3

A function can return a value, the type of value it returns depends on the function.

The return value can be used anywhere outside of the function.