how to sum even numbers less than entry number ?

Question

hi guys 

please help me

 

This is program use c++  i need to sum numbers less than entry numbers i try to print even numbers less than entry but how to sum it ? 

 

#include

using namespace std;

int main() {

/* Initialize i with 1. */

int i;

int n ;

cout << "Enter Number : ";

cin >> n; //take user input

/* If i is less than or equal to 100. */

while( i <= n){

/* If number is divisible by 2, then print.*/

if(i % 2 == 0){

cout <

}

/* Increment i. */

i++;

}

return 0;

}