Reverse order of bits in a given number

Question

The program I am trying to make asks the user for a number, displays that number in binary, and then reverses the order that the bits in the binary number are displayed in.

For instance, if I enter the number 1, the output is displayed as 00000001, and the reverse of that would be printed as 10000000. I have been able to get the number to convert to binary, but I'm not sure how to get the reverse output.

Any suggestions? I have provided my code below so that I can show where I am at in this program.

void print_bits(unsigned char x) {

   int i = 0;

   for (i = 7; i >= 0; i--) {       
     printf("%d", (x & (1 << i)) >> i);
   }    

   printf("\n");    
}

int main(int argc, char * argv[]) {

  unsigned char x;

  printf("Enter a number: ");

  scanf("%hhu", &x);
  printf("Bits: ");
  print_bits(x);

  return 0;
}

Have you tried reversing the for loop to print in the reverse order doing the same operations? — Tyler, Sep 21 '17 at 15:46
There are several previously asked similar questions such as [this one](https://stackoverflow.com/questions/2602823/in-c-c-whats-the-simplest-way-to-reverse-the-order-of-bits-in-a-byte). — Weather Vane, Sep 21 '17 at 15:53
I'm voting to close this question as off-topic because code lacks attempt to meet code's objective. — chux - Reinstate Monica, Sep 21 '17 at 15:56

score 0 · Answer 1 · answered Sep 21 '17 at 15:52

0

Just do the opposit for loop when printing:

for (i = 0; i <= 7; i++) {
    printf("%d", (x & (1 << i)) >> i);
}

answered Sep 21 '17 at 15:52

Franco Pan

128
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Reverse order of bits in a given number

1 Answers1