help me ! some declaration error

[noobnewrecruit]

i got this error ISO C++ forbids declaration of 'VolymCube' with no type .. i think i wrote exactly same as the book ( C++ for beginner in 3 weeks) but the program dont work here is the code.

#include <iostream>

int VolymCube ( int lenght, int width = 25, int height = 1);
using namespace std;
int main ()

{
    
    int lenght = 100;
    int width = 50;
    int height = 25;
    int volym;
    
    volym = VolymCube( lenght,width,height);
    cout << " Volym first round is " << volym << "\n";
    
    
    volym = VolymCube( lenght,width);
    cout << " Volym second round is " << volym << "\n";
    
    
    volym = VolymCube( lenght);
    cout << " Volym third round is " << volym << "\n";
    
    int z;
    cin >> z;
    return 0;
    
}

VolymCube (int lenght, int width, int height)

{
          return ( lenght * width * height);
          
          }