Mutable

Write a program to demonstrate the use of a mutable keyword in CPP.

#include<iostream>
using namespace std;
struct A
{
	int a;
	mutable int b;
};
int main()
{
	const A var = {1,2};
	cout << "a = " << var.a << endl;
	cout << "b = " << var.b << endl;
	//var.a = 45;
	cout << "a = " << var.a << endl;
	var.b = 35;
	cout << "b = " << var.b << endl;
	return 0;
}

Output

a = 1
b = 2
a = 1
b = 35