// CS 31 Example Program// February 20, 2008// John A. Rohr// Pointer Function Examples#include <iostream>#include <iomanip>using namespace std;void exchangeV(int p1, int p2); // Exchange Function:Value Parametersvoid exchangeP(int* p1, int* p2); // Exchange Function: Pointer Parametersvoid exchangeR(int &p1, int &p2); // Exchange Function: Reference Parametersvoid greaterVP(int* p1, int *p2, int* gr); // Greater Function: Value Pointer Parametersvoid greaterRP(int* p1, int* p2, int* &gr); // Greater Function: Reference Pointer Parametersint* greaterPRV(int* p1, int* p2); // Greater Function: Pointer Return Valueint main(){int num1; // First numberint num2; // Second numberint ans; // Answer numberint *p1; // Pointer to first numberint *p2; // Pointer to second numberint *pans; // Pointer to answer number// Set valuesnum1 = 1;num2 = 2;// Display the valuescout << "Main Program Before Call: num1 = " << num1 << endl;cout << "Main Program Before Call: num2 = " << num2 << endl;// Call the exchange function with value parametersexchangeV(num1, num2);// Display the valuescout << "Main Program After Call: num1 = " << num1 << endl;cout << "Main Program After Call: num2 = " << num2 << endl;// Display a blank linecout << endl;// Set valuesnum1 = 3;num2 = 4;// Display the valuescout << "Main Program Before Call: num1 = " << num1 << endl;cout << "Main Program Before Call: num2 = " << num2 << endl;// Call the exchange function with pointer parametersexchangeP(&num1, &num2);// Display the valuescout << "Main Program After Call: num1 = " << num1 << endl;cout << "Main Program After Call: num2 = " << num2 << endl;// Display a blank linecout << endl;// Set valuesnum1 = 5;num2 = 6;// Display the valuescout << "Main Program Before Call: num1 = " << num1 << endl;cout << "Main Program Before Call: num2 = " << num2 << endl;// Call the exchange function with reference parametersexchangeR(num1, num2);// Display the valuescout << "Main Program After Call: num1 = " << num1 << endl;cout << "Main Program After Call: num2 = " << num2 << endl;// Display a blank linecout << endl;// Set valuesnum1 = 11;num2 = 12;ans = -1;// Set pointersp1 = &num1;p2 = &num2;pans = &ans;// Display the valuescout << "Main Program Before Call: num1 = " << num1 << endl;cout << "Main Program Before Call: num2 = " << num2 << endl;cout << "Main Program Before Call: ans = " << ans << endl;// Call the greater function with value pointer parametersgreaterVP(p1, p2, pans);// Display the valuescout << "Main Program After Call: num1 = " << num1 << endl;cout << "Main Program After Call: num2 = " << num2 << endl;cout << "Main Program Before Call: ans = " << ans << endl;// Display a blank linecout << endl;// Set valuesnum1 = 13;num2 = 14;ans = -1;// Set pointersp1 = &num1;p2 = &num2;pans = &ans;// Display the valuescout << "Main Program Before Call: num1 = " << *p1 << endl;cout << "Main Program Before Call: num2 = " << *p2 << endl;cout << "Main Program Before Call: ans = " << *pans << endl;// Call the greater function with reference pointer parametersgreaterRP(p1, p2, pans);// Display the valuescout << "Main Program After Call: num1 = " << *p1 << endl;cout << "Main Program After Call: num2 = " << *p2 << endl;cout << "Main Program Before Call: ans = " << *pans << endl;// Display a blank linecout << endl;// Set valuesnum1 = 15;num2 = 16;ans = -1;// Set pointersp1 = &num1;p2 = &num2;pans = &ans;// Display the valuescout << "Main Program Before Call: num1 = " << *p1 << endl;cout << "Main Program Before Call: num2 = " << *p2 << endl;cout << "Main Program Before Call: ans = " << *pans << endl;// Call the greater function with pointer return valuepans = greaterPRV(p1, p2);// Display the valuescout << "Main Program After Call: num1 = " << *p1 << endl;cout << "Main Program After Call: num2 = " << *p2 << endl;cout << "Main Program Before Call: ans = " << *pans << endl;// Display a blank linecout << endl;// Display a completion messagecout << "Done." << endl;// Returnreturn 0;}// Exchange Function: Value Parametersvoid exchangeV (int p1, int p2){cout << "Exchange Function: Value Parameters" << endl;int hold;hold = p1;p1 = p2;p2 = hold;cout << "In Function: p1 = " << p1 <<endl;cout << "In Function: p2 = " << p2 <<endl;}// Exchange Function: Pointer Parametersvoid exchangeP (int* p1, int* p2){cout << "Exchange Function: Pointer Parameters" << endl;int hold;hold = *p1;*p1 = *p2;*p2 = hold;cout << "In Function: p1 = " << *p1 <<endl;cout << "In Function: p2 = " << *p2 <<endl;}// Exchange Function: Reference Parametersvoid exchangeR (int &p1, int &p2){cout << "Exchange Function: Reference Parameters" << endl;int hold;hold = p1;p1 = p2;p2 = hold;cout << "In Function: p1 = " << p1 <<endl;cout << "In Function: p2 = " << p2 <<endl;}// Greater Function: Value Pointer Parametersvoid greaterVP(int* p1, int* p2, int* gr){cout << "Greater Function: Value Pointer Parameters" << endl;if (*p1 >= *p2){*gr = *p1;}else{*gr = *p2;}}// Greater Function: Reference Pointer Parametersvoid greaterRP(int* p1, int* p2, int* &gr){cout << "Greater Function: Reference Pointer Parameters" << endl;if (*p1 >= *p2){gr = p1;}else{gr = p2;}}// Greater Function: Pointer Return Valueint* greaterPRV(int* p1, int* p2){cout << "Greater Function: Pointer Return Value" << endl;int *p;if (*p1 >= *p2){p = p1;}else{p = p2;}return