C program to find logarithm of number | C Code Champs

C program or source code that calculates and returns logarithm  . For example, if n = 64, then your function should return 6, and if n = 129, then your function should return 7. Let us see how to use C program to find logarithm of number.

Following is a solution using recursion for C program to find logarithm of  number.

#include<stdio.h>

unsigned int Log2n(unsigned int n)
{
   return (n > 1)? 1 + Log2n(n/2): 0;
}

int main()
{
  unsigned int n = 32;
  printf("%u", Log2n(n));
  getchar();
  return 0;
}

Let us try an extended version of the problem.

Writing a one line function Logn(n ,r) which returns . Following is the solution for the extended problem to C program to find logarithm of a number with any base.

#include<stdio.h>

unsigned int Logn(unsigned int n, unsigned int r)
{
   return (n > r-1)? 1 + Logn(n/r, r): 0;
}

int main()
{
  unsigned int n = 256;
  unsigned int r = 4;
  printf("%u", Logn(n, r));
  getchar();
  return 0;
}

Let us know if you face any issues in compiling the codes. Write in form of comments.