fig10_13.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. 10.13: fig10_13.c
   Using the bitwise shift operators */
#include <stdio.h>

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

int main( void )
{ 
   unsigned number1 = 960; /* initialize number1 */

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

   /* demonstrate bitwise right shift */
   printf( "\nThe result of right shifting\n" );
   displayBits( number1 );
   printf( "8 bit positions using the " );
   printf( "right shift operator >> is\n" );
   displayBits( number1 >> 8 );

   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( "%7u = ", 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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