Thread: C Read an integer and count 1s only at positions 2, 4, 6 , 8 of the binary

OK I solved it. As I said I had to solve that only with ONE variable, and count only the bits at positions 2,4,6,8 of a binary code, not ALL THE BITS IN A BINARY CODE. So I CANNOT use a function, or for loops or while loops, because I would need to use more variables. Here is my code:

Code:

#include <stdio.h>
int main()
{
    int x ;


	printf("Enter number: ");
	scanf("%d",&x);
	
printf("%d\n", x & 1);  //pos 1
printf("%d\n", (x >> 1) & 1); //pos 2
printf("%d\n", (x >> 2) & 1); //pos 3
printf("%d\n", (x >> 3) & 1); //pos 4
printf("%d\n", (x >> 4) & 1); //pos 5	
printf("%d\n", (x >> 5) & 1); //pos 6	    
printf("%d\n", (x >> 6) & 1); //pos 7
printf("%d\n", (x >> 7) & 1); //pos 8	


printf("\n\nTotal: %d\n", ((x >> 1) & 1)+((x >> 3) & 1)+((x >> 5) & 1)+((x >> 7) & 1));
	
	return 0;
}

THANK YOU ALL FOR TRYING TO HELP ME !

Hi askis!

May be this example below can help you:

Code:

/** tallybit.c read in a integer value, as a 4-Byte(32Bit) integer
  * and counts the digits where are set and not set.
  * If you read in a negativ integer it shows how does it looks
  * in binary(Two's complement)
  * more information at
  * https://en.wikipedia.org/wiki/Signed_number_representations
  *
  * written by Josef Franz Wismeth, in upper palatinate, bavaria
  *
  * last changes at 2018 December, 26th */

#include <stdio.h>
#include <stdlib.h>


/** counts the number of bits of argument 1, argument_2 = number of bits are set, argument_2 number of bits are not set*/
void tallybin(int intnumber, unsigned int (*bits_set), unsigned int (*bits_not_set))
{
 unsigned int i, grot = 0, result, bits_are_on = 0, bits_are_off = 0, bitsize = 0;

  bitsize = ((sizeof(int)) * 8);

  grot = 1 << (bitsize - 1);

 /// can set the line to a comment
 printf("size of argument 1 in bit: %d\n", bitsize);


for (i = 0; i <= (bitsize - 1); i++)
 {
  result = (unsigned int)intnumber & grot;

  /// shows the bits, can set this two lines to a comment
  if (result) printf("1");
    else printf("0");

  grot >>= 1;
  if (result) bits_are_on++;
   else bits_are_off++;
  }

 (*bits_set) = bits_are_on;
 (*bits_not_set) = bits_are_off;
}


int main()
{
 int number = 0;
 unsigned int bits_on = 0, bits_off = 0;

 printf("Counting the bits!\n");
 printf("Please enter a integer value: ");
 scanf("%d", & number);
 printf("\nThe value was: %d\n", number);

 tallybin(number, &bits_on, &bits_off);



 printf("\nNumber of bits are set: %u\n", bits_on);
 printf("Number of bits not set: %u\n", bits_off);


 return 0;
}

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