static const cached result

Question

In the following example -

#include <iostream>

int someMethod(){
  static int a = 20;
  static const int result = a + 1;
  ++a;
  std::cout << " [" << a << "] ";
  return result;
}

int main(){
  std::cout << someMethod() << "\n";
  std::cout << someMethod() << "\n";
  std::cout << someMethod() << "\n";
}

The output comes as -

[21] 21

[22] 21

[23] 21

What is the reason that is preventing result value to be modified on subsequent calls made to the same function? I've printed the output of variable a as well, which is certainly being incremented and since it is static as well there must not be multiple copies existing for the same method.

IDEONE - COMPILER OUTPUT

Answer 1

Since result is static, it will be initialized only once during runtime.Therefore the following line is executed only once no matter how many times you call someMethod()

 static const int result = a + 1;