fig22_11.cpp

是有关C++编程原理教程的例子程序,全,应该对大家有所帮助

// Fig. 22.11: fig22_11.cpp
// Using the bitwise shift operators.
#include <iostream>
using std::cout;
using std::cin;
using std::endl;

#include <iomanip>
using std::setw;

void displayBits( unsigned ); // prototype

int main()
{
   unsigned number1 = 960;

   // demonstrate bitwise left shift
   cout << "The result of left shifting\n";
   displayBits( number1 );
   cout << "8 bit positions using the left-shift operator is\n";
   displayBits( number1 << 8 );

   // demonstrate bitwise right shift
   cout << "\nThe result of right shifting\n";
   displayBits( number1 );
   cout << "8 bit positions using the right-shift operator is\n";
   displayBits( number1 >> 8 );
   return 0;
} // end main

// display bits of an unsigned integer value
void displayBits( unsigned value )
{
   const int SHIFT = 8 * sizeof( unsigned ) - 1;
   const unsigned MASK = 1 << SHIFT;

   cout << setw( 10 ) << value << " = ";

   // display bits
   for ( unsigned i = 1; i <= SHIFT + 1; i++ ) 
   {
      cout << ( value & MASK ? '1' : '0' );
      value <<= 1; // shift value left by 1

      if ( i % 8 == 0 ) // output a space after 8 bits
         cout << ' ';
   } // end for

   cout << endl;
} // end function displayBits

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