int inputNumber;

cout << "Enter 4-digit number to decrypt: " << endl;

cin >> inputNumber;

// the 4 digits of the number separated

int digit1, digit2, digit3, digit4;

// 1 2 3 4

// digit1 digit2 digit3 digit4

digit4 = (inputNumber / 1)% 10;

digit3 = (inputNumber / 10) % 10;

digit2 = (inputNumber / 100) % 10;

digit1 = (inputNumber / 1000) % 10;

// encryption algorithm

digit1 = (digit1 + 10 - 7) % 10;

digit2 = (digit2 + 10 - 7) % 10;

digit3 = (digit3 + 10 - 7) % 10;

digit4 = (digit4 + 10 - 7) % 10;

int temp;

// swap digit1 and digit3

temp = digit1;

digit1 = digit3;

digit3 = temp;

// swap digit2 and digit4

temp = digit2;

digit2 = digit4;

digit4 = temp;

int encryptedNumber = digit1*1000 + digit2*100 + digit3*10 + digit4;

cout << "The decrypted number is: " << encryptedNumber << endl;

return 0;

}