How to display all even numbers less than a given number?

Question

I need to display all even numbers for that are less than a specific number. Those numbers are random generated between a range. Here's the assignment:

Write a program that prompts the user to enter an integer (n). Your program generates then, another random integer (max) that reaches at most 10 * n. So if n entered was 5, the number generated (max) should be between 5 and 50 (5*10). This program displays the sum of all even numbers less than (max). Your program stops at the first sum value reached greater than max. Display its value.

What I have done so far:

Scanner s = new Scanner(System.in);
System.out.print("Enter an integer: ");

int n = s.nextInt();
int most = (10 * n) - (n+1);
int max = (int)( n + Math.random() * most);

System.out.println("Maximum generated is: "+ max);

for(int i = 2 ; i < max; i+=2) {
    int num = max/i;
    if(num % 2 == 0) {
        System.out.print("number is "+ num);
    }    
}

Sample run:

Enter an integer: 5
Maximum generated is: 45
Sum of (6 8 10 12) = 50 //we stopped because 50 is the first sum greater
                        //than max

What's wrong?

Answer 1

I think your logic should like this,

int sum = 0;
int i = 2;
while (i<max) {
    sum+=i;
    if (sum > max) {
        break;
    }
    i+=2;
}
System.out.print("Value=" + sum);

Answer 2

You can do this:

for(int i=0; i<max; i=i+2){
  sum+=i;
}

System.out.println(sum); It does however sound like there might be an even faster dirrect mathametical formula for fonding the sum of all even numbers bellow a certain number but that's a question for another stack exchange.