Trying to figure out Class and method declaration in Util classes java

Question

I've been having some issues trying to solve this code that my professor sent to me for studying purposes. I usually can solve the isPrime and getPrime no problem but my issue lies with the gcd class. Would love to get some input on this. Thanks :) Sorry for the formatting since i'm new to the site

import java.util.*;

public class Util3
{
  public ??? getSmaller(???)
  {
    int smaller;
    if (???)
      smaller = ???;
    else
      smaller = ???;

    return smaller;
  }

  public ??? gcd(??? a, ??? b)
  {
    int g, smaller;

    smaller = ???(a, b);
    g = smaller;
    for (int i = ???; i >= 1; i++) {  // from smaller to 1
      if (a % i == 0 ??? ???) {
        g = i;
        ???;
      }
    }

    return g;
  }

  public ??? isPrime(int p)
  {
    if (p < 2)
      return false;

    int i;
    for (i = ???; i <= ???; i++)  // from 2 to p-1
      if (??? == 0)  // if p is divisible by i
        break;

    if (i == ???)
      return ???;
    else
      return ???;
  }

  public ??? getPrime(int n)
  {
    boolean b;
    int p;

    for (p = n+1; ; p++) {  // n+1, n+2, ...
      b = ???(p);  // check if p is a prime number
      if (???)
        break;
    }

    return p;
  }
}

Nooblhu · Accepted Answer · 2016-11-20 03:04:59Z

0

You can use a naive solution:

public static int gcd(int a, int b) {
    int current_gcd = 1;
    for(int d = 2; d <= a && d <= b; ++d) {
      if (a % d == 0 && b % d == 0) {
        if (d > current_gcd) {
          current_gcd = d;
        }
      }
    }
    return current_gcd;
  }

Or a recursive one:

public static int GCD(int a, int b) {
    if (b == 0) {
        return a;
        }
     }
    return GCD(b, a % b);
}

answered Nov 20, 2016 at 3:04

Nooblhu

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2 Comments

Kowalchu1 Over a year ago

Thanks for the input! what about a non-static method? It definitely works a lot better but where i am currently in the unit hasn't required a static method involved in the class yet.

Nooblhu Over a year ago

Just remove the static keyword and create a Util3 instance in the Main method

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