fig10_09.c

C程序设计经典教程第5版程序示例,比较适合初级c语言的学生

/* Fig. 10.9: fig10_09.c
   Using the bitwise AND, bitwise inclusive OR, bitwise
   exclusive OR and bitwise complement operators */
#include <stdio.h>

void displayBits( unsigned value ); /* prototype */

int main( void )
{ 
   unsigned number1; /* define number1 */
   unsigned number2; /* define number2 */
   unsigned mask;    /* define mask */
   unsigned setBits; /* define setBits */

   /* demonstrate bitwise AND (&) */
   number1 = 65535;
   mask = 1;
   printf( "The result of combining the following\n" );
   displayBits( number1 );
   displayBits( mask );
   printf( "using the bitwise AND operator & is\n" );
   displayBits( number1 & mask );

   /* demonstrate bitwise inclusive OR (|) */
   number1 = 15;
   setBits = 241;
   printf( "\nThe result of combining the following\n" );
   displayBits( number1 );
   displayBits( setBits );
   printf( "using the bitwise inclusive OR operator | is\n" );
   displayBits( number1 | setBits );

   /* demonstrate bitwise exclusive OR (^) */
   number1 = 139;
   number2 = 199;
   printf( "\nThe result of combining the following\n" );
   displayBits( number1 );
   displayBits( number2 );
   printf( "using the bitwise exclusive OR operator ^ is\n" );
   displayBits( number1 ^ number2 );

   /* demonstrate bitwise complement (~) */
   number1 = 21845;
   printf( "\nThe one's complement of\n" );
   displayBits( number1 );
   printf( "is\n" );
   displayBits( ~number1 );

   return 0; /* indicates successful termination */
} /* end main */

/* display bits of an unsigned integer value */
void displayBits( unsigned value )
{ 
   unsigned c; /* counter */

   /* declare displayMask and left shift 31 bits */
   unsigned displayMask = 1 << 31;

   printf( "%10u = ", value );

   /* loop through bits */
   for ( c = 1; c <= 32; c++ ) { 
      putchar( value & displayMask ? '1' : '0' );
      value <<= 1; /* shift value left by 1 */

      if ( c % 8 == 0 ) { /* output a space after 8 bits */
         putchar( ' ' );
      } /* end if */

   } /* end for */

   putchar( '\n' );
} /* end function displayBits */

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