The **`log2` function** allows users to calculate a number's binary logarithm.




# Library
The `log2` function is accessible from the `math.h` library.
# Syntax
```c
double log2_of_num =  log2(double num)
```
# Parameters
The function takes one #key# parameter: a number for which a binary logarithm is needed #key#. 

>The number needs to be positive (greater than `0`) as the logarithm of negative numbers (and `0`) are undefined.  

# Return value
The `log2` function returns the binary logarithm of the number given as a parameter. The returned number is of datatype `double`.
# Code


#include <stdio.h>
#include <math.h>

int main(){
   double number, log2_of_number;
   number = 32;

   log2_of_number = log2(number); //taking the common log of number
   printf("log10(%lf) = %lf\n", number, log2_of_number);
   // log2 of number will be printed
}

What is log2 in C?

The log2 function returns a number’s binary logarithm, requires a positive parameter, and is available in math.h.