#include <stdio.h>
/* Function to calculate sum of even numbers from 1 to n */
int sumOfEven(int n) {
int sum = 0;
for (int i = 2; i <= n; i += 2) {
sum += i;
}
return sum;
}
int main() {
int n, result;
/* Input */
printf("Enter an integer: ");
scanf("%d", &n);
/* Function call */
result = sumOfEven(n);
/* Output */
printf("Sum of even numbers from 1 to %d = %d\n", n, result);
return 0;
}