PrimeSeive--Corrected

//Matt Zenko
//APCS
//1/7/2017
package com.pepperoni.main;
import java.text.DecimalFormat;
import java.util.Scanner;
public class PrimeSieve {
    public static int totalPrimes = 0, MAX, runningPrime = 0, currIndex = 0;//global variable
    public static void computePrimes(boolean[] primes){//compute primes method
        for(int i = 0; i < primes.length; i++)//initialize primes to true, with 0 and 1 automatically being false
            primes[i] = true;
        primes[0] = false; primes[1] = false;
        System.out.println("Computing...\n");
        for(int i = 2; i < primes.length; i ++)//loops through all of the numbers in primes
            for(int j = 2 * i; j < primes.length; j+=i)//marks all of the multiples of the number starting at 2 * the number as false
                primes[j] = false;                      //Doing so prevents counting the number as a multiple of itself
/*commented below are alternate methods for doing the calculation, although they are not the 'correct' algorithm

        for (int i = 2; i < primes.length; i++){
            for(int j = i; j < primes.length; j++){
                currIndex = i * j;
                if(currIndex < primes.length)primes[currIndex] = false;
                else break;
            }
        }
        for(int i = 2; i < primes.length; i++){//iterates through array
            if(primes[i] == true)//if the number is a prime
                for(int j = i; j < primes.length; j++)//mark all multiples of that number that are not that number as not prime
                    if((j % i == 0) && j != i) primes[j] = false;
        }
*/
    }
    public static void displayPrimes(boolean[] primes){//display primes method
        for(int i = 0; i < primes.length; i++)//find total number of primes
            if(primes[i] == true) totalPrimes++;
        int bigPrime = 0;
        for(int i = primes.length - 1; i > 0; i--)//finds the largest prime number in the set by going through the boolean[] in reverse
            if(primes[i] == true){
                bigPrime = i;
                break;
            }
        int bpl = (int)(Math.log10(bigPrime) + 1);//finds the number of digits that the largest prime has
        StringBuilder formatter = new StringBuilder();
        for(int i = 0; i < bpl; i++)//creates a string with the same number of zeroes that the largest prime has digits
            formatter.append(0);
        DecimalFormat df = new DecimalFormat((new String(formatter)));//new decimal format created based on the size of the largest prime
        System.out.println("There are " + totalPrimes + " primes between 0 and " + (primes.length - 1) + " (inclusive).\n");//prints info
        for(int i = 0; i < primes.length; i++){//if it is prime, format and then print it, followed by a space
            if(primes[i] == true){
                System.out.print(df.format(i) + " ");
                runningPrime++;
                if(runningPrime % 25 == 0) System.out.println();//every 25 primes, go to a new line
            }
        }
        System.out.println("\n\ndone with " + totalPrimes + " total primes");
    }
    public static void main(String[] args) {
        System.out.println("What is the upper bound?");//required main method
        Scanner kbReader = new Scanner(System.in);
        MAX = kbReader.nextInt();
        boolean[] primes = new boolean[MAX + 1];
        computePrimes(primes);
        displayPrimes(primes);
    }
}