ex10_20.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

/* ex10_20.c */
#include <stdio.h>

int mystery( unsigned bits ); /* prototype */

int main( void )
{ 
   unsigned x; /* x will hold an integer entered by the user */

   printf( "Enter an integer: " );
   scanf( "%u", &x );

   printf( "The result is %d\n", mystery( x ) );
   
   return 0; /* indicates successful termination */
} /* end main */

/* What does this function do? */
int mystery( unsigned bits )
{ 
   unsigned i;              /* counter */
   unsigned mask = 1 << 31; /* initialize mask */
   unsigned total = 0;      /* initialize total */

   for ( i = 1; i <= 32; i++, bits <<= 1 ) {

      if ( ( bits & mask ) == mask ) { 
         total++;
      } /* end if */

   } /* end for */

   return !( total % 2 ) ? 1 : 0;
} /* end function mystery */


 

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