io1.cpp

stl自带源码

/* The following code example is taken from the book
 * "The C++ Standard Library - A Tutorial and Reference"
 * by Nicolai M. Josuttis, Addison-Wesley, 1999
 *
 * (C) Copyright Nicolai M. Josuttis 1999.
 * Permission to copy, use, modify, sell and distribute this software
 * is granted provided this copyright notice appears in all copies.
 * This software is provided "as is" without express or implied
 * warranty, and with no claim as to its suitability for any purpose.
 */
#include <cstdlib>
#include <iostream>
using namespace std;

int main()
{
    double x, y;        // operands

    // print header string
    cout << "Multiplication of two floating point values" << endl;

    // read first operand
    cout << "first operand:  ";
    if (! (cin >> x)) {
        /* input error
         *  => error message and exit program with error status
         */
        cerr << "error while reading the first floating value"
             << endl;
        return EXIT_FAILURE;
    }

    // read second operand
    cout << "second operand: ";
    if (! (cin >> y)) {
        /* input error
         *  => error message and exit program with error status
         */
        cerr << "error while reading the second floating value"
             << endl;
        return EXIT_FAILURE;
    }

    // print operands and result
    cout << x << " times " << y << " equals " << x * y << endl;
}