Valor default, volume, profundidade, return, C++

include

int Volume(int compr, int larg = 10, int profund = 12);
int main()
{
int comp, lg, pr;
int vol;
cout << "\nDigite comprimento: ";
cin >> comp;
vol = Volume(comp);
cout << "Volume = "
<< vol
<< "\n";
cout << "\nDigite comprimento: ";
cin >> comp;
cout << "\nDigite largura: ";
cin >> lg;
vol = Volume(comp, lg);
cout << "Volume = "
<< vol
<< "\n";
cout << "\nDigite comprimento: ";
cin >> comp;
cout << "\nDigite largura: ";
cin >> lg;
cout << "\nDigite profundidade: ";
cin >> pr;
vol = Volume(comp, lg, pr);
cout << "Volume = "
<< vol
<< "\n";
return 0;
} 
int Volume(int compr, int larg, int profund)
{
return compr * larg * profund;
}