Unary logical NOT (!) operator overloading program in c++.

/*C++ program for unary logical NOT (!) operator overloading.*/
 
#include<iostream>
using namespace std;
 
class NUM
{
    private:
        int n;
         
    public:
        //function to get number
        void getNum(int x)
        {
            n=x;
        }
        //function to display number
        void dispNum(void)
        {
            cout << "value of n is: " << n;
        }
        //unary ! operator overloading
        void operator ! (void)
        {
            n=!n;
        }
};
int main()
{
    NUM num;
    num.getNum(10);
    cout << "Before calling Operator Overloading:";
    num.dispNum();
    cout << endl;
     
    !num;
    cout << "After  calling Operator Overloading:";
    num.dispNum();
    cout << endl;
    return 0;   
}

Output

    Before calling Operator Overloading:value of n is: 10
    After  calling Operator Overloading:value of n is: 0