C Program for n-th odd number

Given a number N we have to find the N-th odd number.

Odd numbers are the numbers which are not completely divided by 2 and their remainder is not zero. Like 1, 3, 5, 7, 9,….

If we closely observe the list of even numbers we can also represent them as

(2*1)-1=1, (2*2)-1=3,( 2*3)-1=5, (2*4)-1=7,….(2*N)-1.

So, to solve the problem we can simply multiply the number N with 2 and subtract 1 from the result, that makes up an odd number.


Input: 4
Output: 7
The 4th odd number is 1, 3, 5, 7..
Input: 10
Output: 19


   STEP 1 -> Declare and assign an integer ‘n’.
   STEP 2 -> Print n*2-1(odd number).


#include <stdio.h>
int main(int argc, char const *argv[]){
   int n = 10;
   //for odd numbers we can simply subtract 1 to the even numbers
   printf("Nth odd number = %d", n*2-1);
   return 0;


Nth odd number = 19