In this article, I will show you how you can write a C Program to Sum Even numbers in range of 1 to n. I will explain the algorithm, and concepts and then help you to write C Program to Sum Even numbers in range of 1 to n.

## 1. Program Outline

In this program, you’ll have to take two numbers as input from the user and then calculate the Sum Even numbers in the range of 1 to n and display them in the terminal.

## 2. Concepts

To write this C program to Sum Even numbers in the range of 1 to n, you need to learn the following concepts of C Programming:

- Input
- Variables
- while Loop
- If Else

## 3. Algorithm

To write this C program, follow this Algorithm:

Step 1: START Step 2: Input value of n Step 3: Run Loop until n>=0 Step 4: Check n for Even number Step 5: If true add n to sum Step 6: decrease value of n by 1 Step 7: Output value of sum Step 8: STOP

## 4. Program

Here’s the C Program to Sum Even numbers in the range of 1 to n:

```
#include<stdio.h>
int main()
{
int n, sum=0;
printf("Enter the value of n to print sum of even numbers between 1 and n: ");
scanf("%d", &n);
while(n>=1) /* identifying even number */
{
if (n%2==0)
{
sum += n;
}
n -= 1;
}
printf("Sum of even numbers is %d", sum);
}
```

## 5. Output

Here’s the output of the above C Program: