ex3_02.cpp

一本语言类编程书籍

// Exercise 3.2 Calculating the number of boxes that can be stored on a shelf,
// without overhang. We have to calculate how many boxes we can get into a row,
// and how many rows we can have, and then multiply these numbers together.
// The 'no overhang' problem is easily handled: casting from double to long 
// (using static_cast<>()) ensures that the fractional part of the double value
// is omitted, and only whole boxes are counted. 
// By including static_cast<>() in the code, we are effectively telling the
// compiler that we know what information will be lost in the cast.

#include <iostream>
using std::cin;
using std::cout;
using std::endl;

int main() {
  const int inches_per_foot = 12;

  double shelf_length = 0;
  double shelf_depth = 0;
  double box_size = 0;

  // Prompt the user for both the shelf and box dimensions
  cout << "Enter shelf length (feet): ";
  cin >> shelf_length;

  cout << "Enter shelf depth (feet): ";
  cin >> shelf_depth;

  cout << "Enter length ofthe side of a box (inches): ";
  cin >> box_size;

  // Calculating the number of whole boxes needed to fill the shelf.
  long boxes = static_cast<long>((shelf_length * inches_per_foot) / box_size) *
                       static_cast<long>((shelf_depth * inches_per_foot) / box_size);

  // Displaying the number of boxes
  cout << endl
       << "The number of boxes that can be contained in a single layer is "
       << boxes
       << endl;

  return 0;
}