C PROGRAMMING PROGRAM • LOOPS & NUMBER PROBLEMS

Find the Sum of Even Numbers up to N

Learn how to find the sum of even numbers up to n using a clear C program.

BeginnerLoop stepEven numbersAccumulator

PROBLEM UNDERSTANDING

Input and expected output

Sample input

Sample output

Even sum = 30

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int limit;
    long long sum = 0;

    printf("Enter N: ");
    scanf("%d", &limit);
    for (int number = 2; number <= limit; number += 2)
        sum += number;
    printf("Even sum = %lld\n", sum);
    return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Even sum = 30

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Visit only even values by increasing the counter by two.
Display the computed result.

Visit only even values by increasing the counter by two.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(1)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.