C program to print ODD numbers from 1 to N using while loop

This is an example of while loop - In this C program, we are going to learn how can we print all ODD numbers from given range (1 to N) using while loop?
Submitted by Manju Tomar, on March 10, 2018

Given a range (value of N) and we have to print all ODD numbers from 1 to N using while loop.

Example

Input:
Enter value of N: 10

Output:
ODD Numbers from 1 to 10:
1 3 5 7 9

Logic

There are two variables declared in the program 1) number as a loop counter and 2) n to store the limit.
Reading value of n by the user.
Initialising loop counter (number) by 1 as initial value number =1
Using while loop by checking the condition number<=n (value of number is less than or equal to n) - this will execute the loop until the value of number is less than or equal to n.
Then, within the loop, we are checking the condition to check whether number is ODD or not, the condition is (number%2 != 0) - it returns true if number is not divisible by 2.

Program to print ODD numbers from 1 to N using while loop

#include <stdio.h>

int main() {
  //loop counter declaration
  int number;
  //variable to store limit /N
  int n;

  //assign initial value 
  //from where we want to print the numbers
  number = 1;

  //input value of N
  printf("Enter the value of N: ");
  scanf("%d", & n);

  //print statement
  printf("Odd Numbers from 1 to %d:\n", n);

  //while loop, that will print numbers 
  while (number <= n) {
    //Here is the condition to check ODD number
    if (number % 2 != 0)
      printf("%d ", number);

    // increasing loop counter by 1
    number++;
  }

  return 0;
}

Output

Run(1)
Enter the value of N: 10 
Odd Numbers from 1 to 10:
1 3 5 7 9 

Run(2)
Enter the value of N: 100 
Odd Numbers from 1 to 100:
1 3 5 7 9 11 13 15 17 19 21 23 25 27 29 31 
33 35 37 39 41 43 45 47 49 51 53 55 57 59 
61 63 65 67 69 71 73 75 77 79 81 83 85 87 
89 91 93 95 97 99

Another way to print ODD numbers from 1 to N

Since, we know that ODD numbers starts from 1 and ODD numbers are those numbers which are not divisible by 2. So, we can run a loop from 1 to N by increasing the value of loop counter by 2.

Consider the given code...

//initialising the number by 1
number = 1;
//print statement
printf("Odd Numbers from 1 to %d:\n", n);

//while loop, that will print numbers 
while (number <= n) {
  //print the number 
  printf("%d ", number);
  //increase the value of number by 2
  number += 2;
}