Forcing the Explicit Constructor

$ cat test.cpp 

#include <iostream>
#include <string>

class A
{
    public:
        A(int val) { val_ = val; }
        int val_;

};

int main(int argc, char ** argv)
{
    A a1(1);
    std::cout << a1.val_ << std::endl;
    A a2;
    std::cout << a2.val_ << std::endl;
    return 0;
}

$ g++ -Wall test.cpp
test.cpp: In function 'int main(int, char**)':
test.cpp:17: error: no matching function for call to 'A::A()'
test.cpp:8: note: candidates are: A::A(int)
test.cpp:6: note:                 A::A(const A&)
$ 

#include <iostream>
using namespace std;

class myclass
{
  public:
    myclass () { cout << "constructor A called" << endl; }
};


int main (void)
{
cout << "making A" << endl;

myclass A;

cout << "making B" << endl;

myclass B ();

}

$  g++ test1.cpp -o test && ./test

making A
constructor A called
making B

myclass B ();

$ cat test.cpp 

#include <iostream>
#include <string>

class A
{
    public:
        A() { v = 1; std::cout << "A()" << std::endl; }

        int v;
};

A a2()
{
    std:: cout << "calling a2" << std::endl;
    return A();
}

int main(int argc, char ** argv)
{
    A a1;
    A a2();

    std::cout << a1.v << ", " << a2().v << std::endl;
    return 0;
}

$ g++ test.cpp && ./a.out 
A()
calling a2
A()
1, 1
$ 

myclass B ();

B ();

/tmp/ccdtZB7e.o: In function `main':
test1.cpp:(.text+0xc7): undefined reference to `B()'
collect2: ld returned 1 exit status

// dice.h
#include <cstdlib>


class Dice
{
public:
	Dice(const int unsigned numDice, const unsigned int sides);
	void rollDice();
	int getDie(const unsigned int die) const;
	int getDice() const;
	int getSum() const;
	int getPoint() const;
private:
	static const unsigned short MAX_DICE, MAX_SIZE;
	extern const unsigned short NUM_DICE, DICE_SIZE;
	unsigned int *_dice;
	unsigned long _sumOfDice;
};

// dice.cpp
#include "dice.h"


const unsigned short Dice::MAX_DICE = 100;
const unsigned short Dice::MAX_SIZE = 1000;


Dice::Dice( const unsigned int numDice = 2, const unsigned int sides = 6 )
:NUM_DICE((numDice <= MAX_DICE) ? numDice : MAX_DICE), DICE_SIZE((sides <= MAX_SIZE) ? sides : MAX_SIZE)
{
}


void Dice::rollDice()
{
	int dice[NUM_DICE], sum;
	for( unsigned short die = 0; die < NUM_DICE; ++die )
	{
		const roll = 1 + (std::rand() % DICE_SIZE);
		dice[die] = roll;
		sum += roll;
	}
	
	_dice = dice, _sumOfDice = sum;
}


int Dice::getDice() const
{
	return NUM_DICE;
}

int Dice::getDie( const unsigned short die ) const
{
	if( die >= NUM_DICE )
		return -1;

	return _dice[die];
}

int Dice::getSum() const
{
	return _sumOfDice;
}

// main.cpp
#include <cstdlib>
#include <iostream>
#include <string>
#include <sstream>

#include "dice.h"


std::string printSum(Dice *roll);


int main()
{
  std::srand(static_cast<unsigned int>(std::time(0)));

  Dice d1(1, 5);
  std::cout << "d1: " << printSum(d1) << std::endl;
  Dice d2();
  std::cout << "d2: " << printSum(d2) << std::endl;

  return EXIT_SUCCESS;
}

std::string printSum(Dice *roll)
{
  std::ostringstream oss;

  for( unsigned short i = 0; i < roll.getDice() - 1; ++i )
    oss << roll.getDie(i) << " + ";
  oss << roll.getDie(roll.getDice() - 1) << " = " << roll.getSum();

  return oss.str();
}

[brainfrz@li100-29 dice]$ g++ -o main dice.cpp main.cpp
dice.h:15: error: storage class specified for âNUM_DICEâ
dice.h:15: error: storage class specified for âDICE_SIZEâ
dice.cpp: In member function âvoid Dice::rollDice()â:
dice.cpp:19: error: ISO C++ forbids declaration of ârollâ with no type
dice.cpp:24: error: invalid conversion from âint*â to âunsigned int*â
dice.cpp: At global scope:
dice.cpp:33: error: prototype for âint Dice::getDie(short unsigned int) constâ does not match any in class âDiceâ
dice.h:9: error: candidate is: int Dice::getDie(unsigned int) const
dice.h:15: error: storage class specified for âNUM_DICEâ
dice.h:15: error: storage class specified for âDICE_SIZEâ
main.cpp: In function âint main()â:
main.cpp:17: error: cannot convert âDiceâ to âDice*â for argument â1â to âstd::string printSum(Dice*)â
main.cpp:19: error: cannot convert âDice (*)()â to âDice*â for argument â1â to âstd::string printSum(Dice*)â
main.cpp: In function âstd::string printSum(Dice*)â:
main.cpp:28: error: request for member âgetDiceâ in ârollâ, which is of non-class type âDice*â
main.cpp:29: error: request for member âgetDieâ in ârollâ, which is of non-class type âDice*â
main.cpp:30: error: request for member âgetDieâ in ârollâ, which is of non-class type âDice*â
main.cpp:30: error: request for member âgetDiceâ in ârollâ, which is of non-class type âDice*â
main.cpp:30: error: request for member âgetSumâ in ârollâ, which is of non-class type âDice*â

#include "dice.h"


const unsigned short Dice::MAX_DICE = 100;
const unsigned short Dice::MAX_SIZE = 1000;

extern const unsigned short NUM_DICE, DICE_SIZE;

const roll = 1 + (std::rand() % DICE_SIZE);

Dice(const int unsigned numDice, const unsigned int sides);

...

private:
	static const unsigned short MAX_DICE, MAX_SIZE;
	extern const unsigned short NUM_DICE, DICE_SIZE;

#define MAX_DICE 100
#define MAX_SIZE 1000

vector<int> dice;

int[] int_arr = new int[ARR_SIZE];

delete[] int_arr