How to Print a specific amount of spaces per line in Java

Question

I am trying to get a Java program to print a specific amount of spaces per line and then drop down to continue the list. I am finding all prime numbers in a user specified range and then printing out the number of primes in the range and the prime numbers themselves. Anytime the program finds a number that is not a prime number it should print a - . So far, I have:

import java.util.Scanner;

public class PrimeNums {

public static void main(String[] args) {
    Scanner keyboard= new Scanner(System.in);
    int startingVal;
    int endingVal;
    int index;
    int currNum = 2;
    boolean prime;
    int count=0;

    //***  Input  ***

    System.out.println("Enter the Starting Number of the Range: ");
    startingVal = keyboard.nextInt();
    System.out.println("Enter the Ending Value of the Range: ");
    endingVal = keyboard.nextInt();



    //*** Checks for Parameters  ***

    while(startingVal>1000||startingVal%10!=0){
        System.out.println("Starting Value was not evenly divisible by 10. Reenter Starting Value: ");
        startingVal= keyboard.nextInt();
    }
    while(startingVal>=endingVal||endingVal%10!=0||endingVal>1000){
        System.out.println("Ending Value was less than Starting Value or Did Not Follow Guideline. Reenter Ending Value: ");
        endingVal=keyboard.nextInt();
    }


    //***  Stores Checked Variables  ***

    int range = (endingVal);
    int[] primeArray = new int[10];

    //*** Checks for all Prime Numbers  ***

    for(index=startingVal; index<range; index++){

        if(index==1||index%2==0||index%3==0||index%4==0||index%5==0||index%6==0||index%7==0||index%8==0||index%9==0||index%10==0){
            System.out.print("-");
        }else{
            count++;
            System.out.print(index);
        }
    }
    System.out.println("There are " + count + " Prime Numbers in this range.");
}


}

So far, this program finds all the prime numbers within the range and prints them out. However, I need the code to print out in sets of 10. Something like this: Range here is: 70-200.

71 - 73 - - - - - 79 - | 80

- 83 - - - - - 89 - | 90
- - - - 97 - - - | 100

101 - 103 - - - 107 - 109 - | 110

- 113 - - - - - - - | 120
- - - - 127 - - - | 130

131 - - - - - 137 - 139 - | 140

- - - - 149 - | 150

151 - - - - - 157 - - - | 160

- 163 - - - 167 - - - | 170
- 173 - - - - - 179 - | 180

181 - - - - - - - - - | 190

191 - 193 - - - 197 - 199 - | 200

There are 27 prime numbers between 70 and 200

http://stackoverflow.com/questions/388461/how-can-i-pad-a-string-in-java — David, Apr 16 '13 at 00:35
Write a method that can return a `String` which will contain the specified number of spaces. You will need a `while-loop` to achieve it... — MadProgrammer, Apr 16 '13 at 00:35

0x6C38 · Answer 1 · 2013-04-16T01:19:30.690

By subtracting the starting value with index you'll get the loop number, which will be the same as if you were using a counter. Once you know that, %sizeOfSet == 0 will return true if the counter is divisible by sizeOfSet (the number of outputs per set, as you specified, 10).

int sizeOfSet = 10;
if ((index-startingVal) %sizeOfSet == 0){
//prints out an empty line
System.out.printf("%n");
}

This code should be included at the end of the for loop after the if-else statement.

How to Print a specific amount of spaces per line in Java

1 Answers1