exercise1.cpp

《c＋＋大学教程实验指导书》源码

// Chapter 13 of C++ How to Program
// numberverifier.cpp
#include <iostream>

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

#include <cmath>

#include <string>

using std::string;

// class NonNumber definition
class NonNumber : public exception { 
public:

   // constructor
   NonNumber()
      : exception( "non-integer detected" ) 
   {
      // empty

   } // end class NonNumber definition

   /* write definition for method what */

private: 
   string message;

}; // end class NonNumber

// function castInput definition
int castInput( string input )
{
   int result = 0;
   int negative = 1;

   if ( !( input.find_first_not_of( "-0123456789" ) == string::npos ) )
      /* Write code to throw NonNumber exception */

   // check for minus sign
   if ( input[ 0 ] == '-' )
     negative = -1;

   for ( int i = input.length() - 1, j = 0; i >= 0; i--, j++ ) {
         
      if ( negative == -1 && i == 0 )
         continue;

      if ( input[ i ] !=