passbyreference.cpp

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// Tutorial 16: PassByReference.cpp
// This application demonstrates passing by reference using
// reference arguments and pointer arguments.
#include <iostream> // required to perform C++ stream I/O

using namespace std; // for accessing C++ Standard Library members

// function prototypes
void incrementAndDisplay( int & );
void incrementAndDisplay( int * );

// function main begins program execution
int main()
{
   int input = 0; // integer to be passed by reference

   // prompt the user for and input an integer
   cout << "\nEnter an integer: ";
   cin >> input;

   cout << "\nValue in caller before pass-by-reference with a "
        << "reference argument: " << input << endl; 

   incrementAndDisplay( input ); // pass value input a reference

   cout << "Value in caller after incrementing the reference "
        << "argument: " << input << endl;

   cout << "\nValue in caller before pass-by-reference with a "
        << "pointer argument: " << input << endl; 

   incrementAndDisplay( &input ); // pass input using a pointer

   cout << "Value in caller after incrementing the pointer "
        << "argument: " << input << endl;

   cout << endl; // insert newline for readability

   return 0; // indicate that program ended successfully

} // end function main

// uses a reference parameter to increment the function's argument
void incrementAndDisplay( int &count )
{
   count++; // increment count
   cout << "\tInside incrementAndDisplay, value after incrementing"
        << " is: " << count << endl;

} // end function incrementAndDisplay

// uses a pointer parameter to increment the function's argument
void incrementAndDisplay( int *countPointer )
{
   (*countPointer)++; // increment count
   cout << "\tInside incrementAndDisplay, input after incrementing"
        << " is: " << *countPointer << endl;

} // end function incrementAndDisplay


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