I have written a code for converting decimal number to binary number which is not giving desired output

Asked Aug 06 '17 at 06:31

Active Aug 06 '17 at 07:14

Viewed 126 times

//program to give binary equivalent of a decimal number without using recurssion
#include<stdio.h>
#include<math.h>
int main(void)
{
  int i=0,num,bin=0;
  printf("enter number : ");
  scanf("%d",&num);
  while(num>0)
  {
      bin+=((float)(num%2))*pow(10.0,(float)i++);
      num/=2;
  }
  printf("Binary equivalent is : %d",bin);
  getchar();
  return 0;
}

This code dosen't provide desired output for inputs like 7, but does provide desired output for some numbers.Can you please help me out find the error.

edited Aug 06 '17 at 07:14

asked Aug 06 '17 at 06:31

aj14

The reason is you – Antti Haapala -- Слава Україні Aug 06 '17 at 06:44
What output you get for 7 ? – Marian Aug 06 '17 at 06:44
binary equivalent of 7 is 111, but the code is giving 110 – aj14 Aug 06 '17 at 06:45
If you use float instead of integer, any cast back to the integer can be a problem. You shouldn't use floating point in your algorithm. – Tom Kuschel Aug 06 '17 at 06:47
Hmm. Here I get 111. Maybe a bug in your fp arithmetic. Which architecture/compiler do you use? – Marian Aug 06 '17 at 06:50
Yes, but % operator dosen't work with float. – aj14 Aug 06 '17 at 06:51
I use windows 10(64-bit), gcc compiler. – aj14 Aug 06 '17 at 06:51
@aj14 see the duplicate target. `(int)pow(10, 2)` results in 99. 99 + 10 + 1 = 110; but yeah, this is not even a [mcve] as it doesn't state a) the actual result, b) the expected result, c) how to reproduce (i.e. using this GCC version here...). – Antti Haapala -- Слава Україні Aug 06 '17 at 06:52
@aj14: using bin as a float, and print it as %f , then you would see. – Tom Kuschel Aug 06 '17 at 06:53
found alternative, i=1 in initialisation, and in loop bin+=(num%2)*i;i*=10;num/=2; – aj14 Aug 06 '17 at 07:02
@aj14: you're absolutely right, avoid casts from floating point to integer, and use integer `i*=10`. You should answer your question by yourself. – Tom Kuschel Aug 06 '17 at 07:09
You are converting a decimal number to binary with `scanf("%d",&num)`, and the remaining code converts. or is supposed to convert, a binary number to something else. Unclear what you're asking. – user207421 Aug 06 '17 at 07:12
bin = 0; factor = 1; do { bin += factor * (num & 1); num >>= 1; factor *= 10; } while (num > 0); – SBS Aug 06 '17 at 07:31

I have written a code for converting decimal number to binary number which is not giving desired output

0 Answers0