Function Prototyping in c++ with example and code

 // Prototypes  
 void DisplayMenu();  
 int GetSelection();  
 // The main() function.  
 int main()  
 {  
 // Display the menu.  
 DisplayMenu();  
 // Get the menu selection.  
 int selection;  
 selection = GetSelection();  
 // Select the matching process.  
 if (selection == 1)  
 std::cout << "Processing Receivables" << std::endl;  
  else if (selection == 2)  
  std::cout << "Processing Payables" << std::endl;  
 else if (selection == 3)  
 std::cout << "Quitting" << std::endl;  
 else std::cout << "\aInvalid selection" << std::endl; return 0;  
 }  
 void DisplayMenu()  
 {  
 std::cout << "--- Menu ---" << std::endl;  
 std::cout << "1=Receivables" << std::endl;  
 std::cout << "2=Payables" << std::endl;  
 std::cout << "3=Quit" << std::endl;  
 }  
 int GetSelection()  
 {  
 int selection; std::cout << "Enter Selection: "; std::cin >> selection;  
 return selection;  
 }