Constructors with Arguments

• Constructors can take arguments, allowing (or even forcing) the user specify some initialization information when creating an instance of a class.

class counter {

private:

int counter_p;

public:

// We are defining a constructor that takes an argument --

// so the default constructor is not generated

counter(int initial_value) { counter_p = initial_value; }

// ...same increment(), decrement(), and get_value()

};

counter a; // ILLEGAL - compile-time error because the

// default constructor no longer exists!

counter b(4); // Ok!

counter c(“Hi”); // ILLEGAL - Expecting int, got char *

counter d(4, 5); // ILLEGAL - Expecting one int, got two

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