reversedigits.cpp

《c＋＋大学教程实验指导书》源码

// Chapter 3 of C++ How to Program
// reversedigits.cpp
#include <iostream>

using std::cout;
using std::cin;
using std::endl;

#include <iomanip>

using std::setw;

/* write prototype for reverseDigits */
/* write prototype for width */

int main()
{
   int number;

   cout << "Enter a number between 1 and 9999: ";
   cin >> number;
   cout << "The number with its digits reversed is: "
        << setw( /* write call for width */ )
        << /* write call for reverseDigits */
        << endl;

   return 0;

} // end main

// function reverseDigits definition
/* write function header for reverseDigits */
{
   int reverse = 0;
   int divisor = 1000; 
   int multiplier = 1;

   while ( n > 10 ) {

      if ( n >= divisor ) {
         reverse += n / divisor * multiplier;
         n %= divisor;
         /* write a line of code that reduces divisor by a factor    
         of 10 */
       /* write a line of code that increases multiplier
          by a factor of 10 */

      } // end if
      else
         divisor /= 10;

   } // end while
   
   reverse += n * multiplier;
   return reverse;

} // end function reverseDigits

// function width definition
/* write function header for width */
{
    if ( n / 1000 )
       return 4;
    else if ( n / 100 )
       return 3;
    else if ( n / 10 )
       return 2;
    else
       return 1;

} // end function width



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