fig20_06.cpp

来自「《c＋＋大学教程》源码」· C++ 代码 · 共 85 行

// Fig. 20.6: fig20_06.cpp
// Using signal handling 
#include <iostream>

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

#include <iomanip>

using std::setw;

#include <csignal>
#include <cstdlib>
#include <ctime>

void signalHandler( int );

int main()
{
   signal( SIGINT, signalHandler );
   srand( time( 0 ) );
   
   // create and output random numbers
   for ( int i = 1; i <= 100; i++ ) {
      int x = 1 + rand() % 50;
      
      // raise SIGINT when x is 25
      if ( x == 25 )
         raise( SIGINT );
         
      cout << setw( 4 ) << i;

      // output endl when i is a multiple of 10
      if ( i % 10 == 0 )
         cout << endl;

   }  // end for

   return 0;

}  // end main

// handles signal
void signalHandler( int signalValue )
{
   cout << "\nInterrupt signal (" << signalValue
        << ") received.\n"
        << "Do you wish to continue (1 = yes or 2 = no)? ";

   int response;  

   cin >> response;

   // check for invalid responses
   while ( response != 1 && response != 2 ) {
      cout << "(1 = yes or 2 = no)? ";
      cin >> response;

   }  // end while
   
   // determine if it is time to exit
   if ( response != 1 )
      exit( EXIT_SUCCESS );

   // call signal and pass it SIGINT and address of signalHandler
   signal( SIGINT, signalHandler );
      
}  // end function signalHandler

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