CODEWITHSUNDEEP
javaloopsfor-loopprinting
frowit
frowit

Reputation: 45

How can I print in a box pattern or any sort of pattern?

What I mean by that is when I print, for example, a Sieve of Eratosthenes, it just prints a long line of numbers vertically with println(). With print(), it just prints another long line horizontally. I want it so that there's some sort of line you can't go across to.

I attached a snip and for a clearer objective, I drew a red box of where I want the numbers to stop, and where to start.

a snip with a red box

Upvotes: 1

Views: 284

Answers (2)

Anuj
Anuj

Reputation: 1665

There are many ways to achieve this. Here is one way. Suppose you are printing natural numbers from 1 to n and you want only 10 natural numbers in a line, then you can do this:

for (int i = 1; i <= n; i++) {
    System.out.print(i + " ");

    //Add new line if there are 10 elements in a row
    if (i % 10 == 0) System.out.println();
}

If you are working with Sieve of Eratosthenes, then the numbers to be printed do not follow a regular sequence. In that case, you can count the number of numbers printed and add a new line accordingly.

Suppose you have a boolean array numbers where if the index of the array represents a Prime number, then at that index true is stored or else false is stored. In that case you may use this:

int count = 0;
for (int i = 1; i <= n; i++) {
    if (numbers[i]) {
        System.out.print(i + " ");
        count++;
    }

    if (count == 10) {
        System.out.println();
        count = 0;
    }
}

I should add, if you still want to add more symmetry in your output so that there is proper spacing and the elements appear one below the other, you can replace System.out.print (i + " ") with System.out.print (i + "\t").

The output will appear more beautiful and it will be more readable.

I hope I have helped you.

Upvotes: 2

user14940971
user14940971

Reputation:

You can use IntStream for this purpose:

IntStream.rangeClosed(11, 40)
        // print elements in one line
        .peek(i -> System.out.print(i + " "))
        // after every tenth element
        .filter(i -> i % 10 == 0)
        // print new line
        .forEach(i -> System.out.println());

Output:

11 12 13 14 15 16 17 18 19 20 
21 22 23 24 25 26 27 28 29 30 
31 32 33 34 35 36 37 38 39 40

Upvotes: 0

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