Question

Should SomeClass* initialEl = new SomeClass[5]; necessarily compile, assuming SomeClass does not have a non-publicly declared default constructor? Consider:

/*
 * SomeClass.h
 *
 */

#ifndef SOMECLASS_H_
#define SOMECLASS_H_

class SomeClass
{

public:
    SomeClass(int){}
    ~SomeClass(){}
};

#endif /* SOMECLASS_H_ */


/*
 * main.cpp
 *
 */

#include "SomeClass.h"

int main()
{
    SomeClass* initialEl = new SomeClass[5];

    delete[] initialEl;

    return 0;
}

Answer 1

No, it won’t compile without a default constructor. There is no compiler-generated default constructor in this case, because you have defined another constructor. “The compiler will try to generate one if needed and if the user hasn’t declared other constructors.” — The C++ Programming Language, Stroustrup

If you really want to use new SomeClass[5], you’ll have to provide a default constructor as well.