Can any one tell me how to convert a float to binary..

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hi i am a beginner to c programming. i want to know how to convert a float to binary. please explain with example.

Posted 5-Nov-13 0:19am

asifmohammad

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Comments

Richard MacCutchan 5-Nov-13 7:16am

What do you mean by convert; convert to an integer, or convert to a printable format?

Stefan_Lang 5-Nov-13 11:04am

You seem to be confusing two (mostly) unrelated concepts - or you haven't expressed your question well:

"float" is a data type used to describe the kind of value a variable of that type contains: it is a number that may contain a fractional part and/or an exponent. Examples would be:
5, -6.23, 3.1415, -0.739e-11

"binary" is a specific representation of a numeric value in the form of a string of '0's and '1's. E. g. you can represent the number 5 by writing it in its binary representation as "%101" (where the leading '%' indicates a number in binary notation as per the C/C++ standard)

Anyway, the representation of a number is something different than a type. You can print a binary representation of a floating point number, but doing so does not convert or otherwise affect the original value.

Hamed Moezzi Azimi 5-Nov-13 12:57pm

Your answer is in here:
http://stackoverflow.com/questions/3954498/how-to-convert-float-number-to-binary

5 solutions

Solution 1

Binary? You mean you want to read the bytes of it? You can use a union for that. Every field in a union represents the same data in memory.

C#

union floatUnion_t {
    float f;
    char bytes[sizeof float]
} floatUnion1;

With this union you can read/write f as a float and read/write the bytes of it as well.

Good luck!

Posted 5-Nov-13 0:32am

E.F. Nijboer

Solution 5

There is a function that convert int* into binary.
So get your float's address & cast it to int* then convert it into binary by inbuilt function

C++

float MyFloat = 10.5;
float *p;
p = &MyFloat;
convert_int_to_binary_string(*((int*)p));

This Might work for you.

OR one can refer this too.
this may be help you.
http://stackoverflow.com/questions/12868444/convert-float-to-binary-in-c[^]
http://www.cquestions.com/2011/07/c-program-for-fractional-decimal-to.html[^]

Hope This Help
------------------
Pratik Bhuva

Posted 7-Nov-13 23:39pm

Pratik Bhuva

Updated 7-Nov-13 23:42pm

v2

Comments

nv3 8-Nov-13 7:37am

This is doing actually the opposite: It converts a float (which is stored in binary format) into a text representation.

Solution 2

#include <iostream>
#include <bitset>

int main()
{
union
{
float input; // assumes sizeof(float) == sizeof(int)
int output;
} data;

data.input = 2.25125;

std::bitset<sizeof(float)> bits(data.output);

std::cout << bits << std::endl;

// or

std::cout << "BIT 4: " << bits[4] << std::endl;
std::cout << "BIT 7: " << bits[7] << std::endl;
}

Posted 5-Nov-13 1:16am

HAMZEI

Solution 3

Hi,

Numbers could be change to binary through dividing by 2 until it becomes less than 2;

Posted 7-Nov-13 22:56pm

dashti55

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CPallini · Accepted Answer · 2013-11-07T23:39:00

There is no conversion from float to binary since float variables are already stored in the binary form stated by the IEEE_754 standard[^].

If you need to show how a float is stored in a human friendly format, then you may use, for instance, the following code:

C

#include <stdio.h>


void out_float(float f)
{
  size_t size = sizeof(f);
  unsigned char * p = (unsigned char *) &f;
  p += size-1;
  while (size--)
  {
    int n;
    for (n=0; n<8; n++)
    {
      putchar('0' + (*p & 128 ? 1 : 0));
      *p <<= 1;
    }
    p--;
  }
}


int main()
{
  float f = -118.625f;

  out_float(f);
  putchar('\n');
  return 0;
}