Explicit Conversion

In C++, we could restrict the conversion of constructor’s argument to use direct-initialisation instead of copy-initialisation.

The differences between them are shown below: 

Vector v1{7}; // direct-initialisation
Vector v1 = 7; // copy-initialisation

To do this, we could add the specifier explicit onto the Vector constructor: 

class Vector {
  public:
    explicit Vector(int s);
}

The compiler will recognise that restriction on the conversion is necessary on the Vector and prohibit such conversion during compile time. 

Vector v1{7}; // OK
Vector v1 = 7; // error in compile time
#cpp