How to Calculate Log Base 2 in C/C ?

How to Calculate Log Base(2) in C/C

In C/C , there are two built-in logarithmic functions: log (base e) and log10 (base 10). However, for calculations involving log base(2), these functions are not directly applicable.

Mathematical Solution:

A simple mathematical approach to calculate log base(2) is:

log<sub>2</sub> (<em>x</em>) = log<sub><em>y</em></sub> (<em>x</em>) / log<sub><em>y</em></sub> (2)

where y can be any base. For clarity in C/C , this equation becomes:

<code class="c">log2(x) = log(x) / log(2);</code>

This formula allows you to calculate log base(2) using the existing log function, which takes an arbitrary base.

Example:

To calculate log base(2) of the number 16:

<code class="c">#include <stdio.h>
#include <math.h>

int main() {
  double x = 16;
  double log2 = log(x) / log(2);

  printf("log base(2) of %f is: %.2f\n", x, log2);

  return 0;
}</code>

Output:

log base(2) of 16.000000 is: 4.00

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