carpayment.cpp

C++大学简明教程,解压就行没有密码。希望对大家有用

// Tutorial 20: CarPayment.cpp
// Calculate different billing plans for a car loan.
#include <iostream> // required to perform C++ stream I/O
#include <iomanip> // required for parameterized stream manipulators
#include <cmath> // required to use the C++ math library functions
#include <string> // required to access string functions

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

// function prototypes
double calculateMonthlyPayment( double, int, int );
void processData( int, int, double );

// function main begins program execution
int main()
{
   // define variables
   int price; // price of the car
   int downPayment; // the down payment
   double interest; // the annual interest rate

   // prompt user for and input the car price, the
   // down payment and the annual interest rate
   cout << "\nEnter the car price: ";
   cin >> price; // get the car price

   cout << "Enter the down payment: ";
   cin >> downPayment; // get the down payment

   cout << "Enter the annual interest rate: ";
   cin >> interest; // get the annual interest rate

   // create table of options over different periods of time
   processData( price, downPayment, interest); 

   return 0; // indicate that program ended successfully

} // end function main

// function calculates payments for each time interval
void processData( int price, int downPayment, double interest )
{
   // calculate loan amount and monthly interest
   int loanAmount = price - downPayment;
   double monthlyInterest = interest / 1200;
   
   // set precision for output values
   cout << fixed << setprecision( 2 );

   // add header to output
   cout << endl << left << setw( 10 ) << "Months" 
        << "Monthly Payments" << endl;

   // calculate and display payments
   for ( int years = 2; years <= 5; years++ )
   {
      // convert payment period to months
      int months = 12 * years; 
      
      // get monthlyPayment         
      double monthlyPayment = calculateMonthlyPayment( 
         monthlyInterest, months, loanAmount );

      // insert result into output stream
      cout << left << setw( 10 ) << months 
           << "$" << monthlyPayment << endl;

   } // end for

} // end function processData

// calculate monthlyPayment
double calculateMonthlyPayment( double monthlyInterest,
   int months, int loanAmount )
{
   double base = pow( 1 + monthlyInterest, months );

   return loanAmount * monthlyInterest / ( 1 - ( 1 / base ) );

} // end function calculateMonthlyPayment

 /**************************************************************************
  * (C) Copyright 1992-2005 by Deitel & Associates, Inc. and               *
  * Pearson Education, Inc. All Rights Reserved.                           *
  * DISCLAIMER: The authors and publisher of this book have used their     *
  * best efforts in preparing the book. These efforts include the          *
  * development, research, and testing of the theories and programs        *
  * to determine their effectiveness. The authors and publisher make       *
  * no warranty of any kind, expressed or implied, with regard to these    *
  * programs or to the documentation contained in these books. The authors *
  * and publisher shall not be liable in any event for incidental or       *
  * consequential damages in connection with, or arising out of, the       *
  * furnishing, performance, or use of these programs.                     *
  **************************************************************************/