C Exercises: Display the sum of n number of odd natural number

Last update on March 18 2025 13:34:51 (UTC/GMT +8 hours)

8. Odd Natural Numbers and Their Sum

Write a C program to display the n terms of odd natural numbers and their sum.
like: 1 3 5 7 ... n

This C program displays the first 'n' odd natural numbers and calculates their sum. The user inputs the value of 'n', and the program generates a sequence of odd numbers starting from 1. Using a "for" loop, it sums these odd numbers and displays both the sequence and the total sum.

Visual Presentation:

Display the sum of n number of odd natural number

Sample Solution:

C Code:

#include <stdio.h>  // Include the standard input/output header file.

void main() {
    int i, n, sum = 0;  // Declare variables 'i' for loop counter, 'n' for user input, and 'sum' to store the sum.

    printf("Input number of terms : ");  // Print a message to prompt user input.
    scanf("%d", &n);  // Read the value of 'n' from the user.
    printf("\nThe odd numbers are :");  // Print a message indicating that odd numbers will be displayed.

    for (i = 1; i <= n; i++) {  // Start a loop to generate odd numbers based on user input.
        printf("%d ", 2 * i - 1);  // Print the odd number.
        sum += 2 * i - 1;  // Add the odd number to the running sum.
    }

    printf("\nThe Sum of odd Natural Number upto %d terms : %d \n", n, sum);  // Print the sum of odd numbers.

}

Output:

Input number of terms : 10                                                                                    
                                                                                                              
The odd numbers are :1 3 5 7 9 11 13 15 17 19                                                                 
The Sum of odd Natural Number upto 10 terms : 100

Explanation:

for (i = 1; i <= n; i++) {
  printf("%d ", 2 * i - 1);
  sum += 2 * i - 1;
}

In the said loop, the variable i is initialized to 1, and the loop will continue as long as i is less than or equal to the value of variable 'n'. In each iteration of the loop, the printf function will print the value of (2*i-1) to the console, followed by a space character.

Additionally, the value of (2*i-1) will be added to the variable 'sum' in each iteration of the loop.

The loop will increment the value of i by 1, and the process will repeat until the condition i<=n is no longer true.

Flowchart:

For more Practice: Solve these Related Problems:

Write a C program to display the first n odd natural numbers and compute their product instead of sum.
Write a C program to display odd natural numbers up to n and calculate both their sum and average.
Write a C program to display odd natural numbers in reverse order up to n and then compute the sum.
Write a C program to generate odd natural numbers recursively and display their cumulative sum at each term.

C Programming Code Editor:

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