Визначити, яке з чисел дорівнює d, якщо жодне з чисел не рівне d, то знайти max{d-a, d-b, d-c}

#include <iostream>

using namespace std;

int main()

{

       int a, b, c, d;

       cout << "Enter a: ";

       cin >> a;

       cout << "Enter b: ";

       cin >> b;

       cout << "Enter c: ";

       cin >> c;

       cout << "Enter d: ";

       cin >> d;

       if (a != d && b != d && c != d) {

             a = d - a;

             cout << "a = " << a << endl;

             b = d - b;

             cout << "b = " << b << endl;

             c = d - c;

             cout << "c = " << c << endl;

             int max;

             if (a > b && a > c) {

                    max = a;

                    cout << "Max = " << max << endl;

             }

             if (b > a && b > c) {

                    max = b;

                    cout << "Max = " << max << endl;

             }

             if (c > a && c > b) {

                    max = c;

                    cout << "Max = " << max << endl;

             }

       }

       else if (d == a && d != b && d != c)

             cout << "d is equal to a! " << endl;

       else if (d == b && d != a && d != c)

             cout << "d is equal to b! " << endl;

       else if (d == c && d != a && d != b)

             cout << "d is equal to c! " << endl;

       else if (d == a && d == b && d != c)

             cout << "d is equal to a and b! " << endl;

       else if (d == b && d == c && d != a)

             cout << "d is equal to b and c! " << endl;

       else if (d == a && d == c && d != b)

             cout << "d is equal to a and c! " << endl;

       else if (d == a && d == b && d == c)

             cout << "d is equal to a, b and c! " << endl;

       getchar();

       getchar();

       return 0;

}