Can two non-nested for loops be condensed into one?

Question

I have a sample question where we are required to find multiples of 10 between two numbers. Here's the code I've written, and although it works, is there a better way to write this code?

Scanner keyboard = new Scanner(System.in);
    int value = keyboard.nextInt();
    int limit = keyboard.nextInt();
    int div = 10;

    for (;div<value;div+=10)
        System.out.print("");

    for (;div<=limit;div+=10)
        System.out.println(div);

    keyboard.close();

The first for loop irks me. Any suggestions?

Answer 1

Using java-8 :

IntStream.rangeClosed(value, limit).filter(i -> i % 10 == 0).forEach(System.out::println);

Here value is the begin index and limit is the ending index.

Answer 2

System.out.print("") does nothing, so your first loop can be re-written as:

int div = 10;
for (; div < value; div += 10)
    ;

The effect of that code is that div is the value of value rounded up to the nearest multiple of 10. This can be calculated as follows, using int math (where division by 10 rounds down):

int div = (value + 9) / 10 * 10;

The original code will result in a minimum value of 10 , so if value <= 0 the formula will calculate incorrectly. We can use a ternary conditional operator to account for that:

int div = (value <= 10 ? 10 : (value + 9) / 10 * 10);

So, the abbreviated version of your code becomes:

Scanner keyboard = new Scanner(System.in);
int value = keyboard.nextInt();
int limit = keyboard.nextInt();

for (int div = (value <= 10 ? 10 : (value + 9) / 10 * 10); div <= limit; div += 10)
    System.out.println(div);

keyboard.close();