#include <iostream>

//function prototype or function definition
void funct1 (int);
void funct2 (int&);   // & is needed to specify pass-by-reference

int main()
{
 int var1;

 var1 = 10;

 cout << "Before the first function call, Var1 is: " << var1 << endl;

 funct1(var1);

 cout << "After the first function call, Var1 is: " << var1 << endl;

 cout << "Before the second function call, Var1 is: " << var1 << endl;

 funct2(var1);

 cout << "After the second function call, Var1 is: " << var1 << endl;
}

// This function shows how a "pass-by-value" parameter works
void funct1 (int param1)
{
 cout << "In the function, param1 is: " << param1 << endl;

 param1++;

 cout << "In the function, param1 is: " << param1 << endl;
}

// This function shows how a "pass-by-reference" parameter works
//   The & before the parameter name indicates a pass-by-reference 
//    parameter.
void funct2 (int &param1)
{
 cout << "In the function, param1 is: " << param1 << endl;

 param1++;

 cout << "In the function, param1 is: " << param1 << endl;
}