No matching function for call to Class Constructor

Question

I am practicing my OOP and I have the following classes: Point and Circle. Specifically, Circle has a center Point, and a radius. Here is the relevant code:

Answer 1

In trying to construct Circle, you tried to construct a Point using a default constructor:

Circle::Circle(const Point& center, double radius)
                     ^
                //...Calling default constructor...

...and then assigned it a value:

center_pt = center;

Given that the default constructor didn't exist, you got the compile-time error.

Two solutions are:

1) Construct a Point using a member initialisation list:

Circle::Circle(const Point& center, double radius): center_pt(center), 
                                                    radius_size(radius) {
}

2) Define a default constructor for Point:

Point::Point(){

}

I am primarily answering this question to place emphasis on option 2 as I believe this emphasis was lacking in the answers above. Sometimes, it is more practical to default construct an object in a givens class parameter list and assign it a value at a later stage. This is encountered a bit in GUI programming in using the Qt framework.