Write a C program to input number from user and find sum of all even numbers between 1 to n. How to find sum of even numbers in a given range using loop in C programming. Logic to find sum of even numbers in a given range in C program.

**Example**

**Input**

Input upper limit of even number: 10

**Output**

Sum of even numbers between 1 to 10: 30

## Required knowledge

Basic C programming, Relational operators, For loop

Learn more - Program to check even numbers.

## Logic to find sum of even numbers

Step by step descriptive logic to find sum of even numbers.

- Input upper limit to find sum of even number. Store it in some variable say
`N`. - Initialize another variable to store sum with 0 say
`sum = 0`

. - To find sum of even numbers we need to iterate through even numbers from 1 to n. Initialize a loop from
`2`to`N`and increment`2`on each iteration. The loop structure should look like`for(i=2; i<=N; i+=2)`

. - Inside the loop body add previous value of
`sum`with`i`i.e.`sum = sum + i`

. - After loop print final value of
`sum`.

## Program to find sum of even numbers

```
/**
* C program to print sum of all even numbers between 1 to n
*/
#include <stdio.h>
int main()
{
int i, n, sum=0;
/* Input upper limit from user */
printf("Enter upper limit: ");
scanf("%d", &n);
for(i=2; i<=n; i+=2)
{
/* Add current even number to sum */
sum += i;
}
printf("Sum of all even number between 1 to %d = %d", n, sum);
return 0;
}
```

**Note:** Do not confuse with the shorthand assignment operator `sum += i`

. It is equivalent to `sum = sum + i`

.

Output

Enter upper limit: 10 Sum of all even number between 1 to 10 = 30

## Program to find sum of even numbers in given range

```
/**
* C program to print sum of all even numbers in given range
*/
#include <stdio.h>
int main()
{
int i, start, end, sum=0;
/* Input lower and upper limit from user */
printf("Enter lower limit: ");
scanf("%d", &start);
printf("Enter upper limit: ");
scanf("%d", &end);
/* If start is not even then make it even */
if(start%2!=0)
{
start++;
}
for(i=start; i<=end; i+=2)
{
/* Add current even number to sum */
sum += i;
}
printf("Sum of all even number between %d to %d = %d", start, end, sum);
return 0;
}
```

Output

Enter lower limit: 6 Enter upper limit: 10 Sum of all even number between 6 to 10 = 24

Happy coding 😉

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