View difference between Paste ID: dKtJSiQJ and 2Q4r6v9v

 /*
 It does not support combinations that start with one or more zeroes. For example, a combination of 0042 can be opened by entering just 42.
 
 Solve this problem by choosing a different representation. Instead of an integer, use a string to hold the input.
 */
 #include <iostream>
 #include <string>
 using namespace std;
 
 /**
    A simulated lock with digit buttons.
 */
 class Lock
 {
 public:
    /**
       Simulates a digit button push.
       @param button a digit 0 ... 9
    */
    void push(int button);
 
    /**
       Simulates a push of the open button.
       @return true if the lock opened
    */
    bool open();
 private:
    string combination = "0042";
    string input;
 };
 
 void Lock::push(int button)
 {
    string button_as_string = to_string(button);
    . . .
 }
 
 bool Lock::open()
 {
    . . .
 }
 
 int main()
 {
    Lock my_lock;
    my_lock.push(4);
    my_lock.push(2);
    cout << boolalpha;
    cout << my_lock.open() << endl;
    cout << "Expected: false" << endl;
    my_lock.push(0);
    my_lock.push(0);
    my_lock.push(4);
    my_lock.push(2);
    cout << my_lock.open() << endl;
    cout << "Expected: true" << endl;
    my_lock.push(0);
    my_lock.push(4);
    my_lock.push(2);
    cout << my_lock.open() << endl;
    cout << "Expected: false" << endl;
    my_lock.push(0);
    my_lock.push(0);
    my_lock.push(0);
    my_lock.push(4);
    my_lock.push(2);
    cout << my_lock.open() << endl;
    cout << "Expected: false" << endl;
    my_lock.push(0);
    my_lock.push(0);
    my_lock.push(4);
    my_lock.push(2);
    cout << my_lock.open() << endl;
    cout << "Expected: true" << endl;
    return 0;
 }