C program to find sum of odd numbers from 1 to n

Write a C program to find sum of all odd numbers from 1 to n using for loop. How to find sum of all odd numbers in a given range in C programming. Logic to find sum of odd numbers in a given range using loop in C programming.

Example

Input

Input upper limit: 10

Output

Sum of odd numbers from 1-10: 25

Required knowledge

Basic C programming, Relational operators, For loop

Learn more - Program to check odd numbers.

Logic to find sum of odd numbers from 1 to n

Step by step descriptive logic to find sum of odd numbers between 1 to n.

  1. Input upper limit to find sum of odd numbers from user. Store it in some variable say N.
  2. Initialize other variable to store sum say sum = 0.
  3. To find sum of odd numbers we must iterate through all odd numbers between 1 to n. Run a loop from 1 to N, increment 1 in each iteration. The loop structure must look similar to for(i=1; i<=N; i++).
  4. Inside the loop add sum to the current value of i i.e. sum = sum + i.
  5. Print the final value of sum.

Program to find sum of odd numbers from 1 to n

/**
 * C program to print the sum of all odd numbers from 1 to n
 */

#include <stdio.h>

int main()
{
    int i, n, sum=0;

    /* Input range to find sum of odd numbers */
    printf("Enter upper limit: ");
    scanf("%d", &n);

    /* Find the sum of all odd number */
    for(i=1; i<=n; i+=2)
    {
        sum += i;
    }

    printf("Sum of odd numbers = %d", sum);

    return 0;
}

Note: Do not confuse with the shorthand assignment operator sum += i. It is equivalent to sum = sum + i.

Program to find sum of odd numbers in given range

/**
 * C program to print the sum of all odd numbers in given range
 */

#include <stdio.h>

int main()
{
    int i, start, end, sum=0;

    /* Input range to find sum of odd numbers */
    printf("Enter lower limit: ");
    scanf("%d", &start);
    printf("Enter upper limit: ");
    scanf("%d", &end);

    /* If lower limit is even then make it odd */
    if(start % 2 == 0)
    {
        start++;
    }
    
    /* Iterate from start to end and find sum */
    for(i=start; i<=end; i+=2)
    {
        sum += i;
    }

    printf("Sum of odd numbers between %d to %d = %d", start, end, sum);

    return 0;
}

Output

Enter lower limit: 4
Enter upper limit: 11
Sum of odd numbers between 4 to 11 = 32

Happy coding 😉

About Pankaj

Pankaj Prakash is the founder, editor and blogger at Codeforwin. He loves to learn new techs and write programming articles especially for beginners. He works at Vasudhaika Software Sols as a Software Design Engineer and manages Codeforwin. In short Pankaj is Web developer, Blogger, Learner, Tech and Music lover.

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