#include <iostream>

using namespace std;

void func(int a,int b, int c=3);
void func(int a,int b = 5, int c);
void func(int a = 10, int b, int c);

void func(int a, int b, int c)
{
    cout << "a = " << a
      << " b = " <<b <<" c= " <<c <<endl;
}

int main()
{
    func(20);
    func(15,20);
    func(15,20,30);
    func(20,30);
    func();
    return 0;
}