simple_programs

Nitin P Wadakar

Completed M.Tech in IT from VIT, Vellore and he is a fresher from Bengaluru. Helped in contributing these programs.




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CommonUtils class is an utility class and any class can reuse methods from it.

1. Read input from keyboard and used as a common class.

package com.thebeautifuljava.utils;

import java.util.Scanner;

public class CommonUtils {

 public static int readFromKeyBoard() {
  Scanner scanner = new Scanner(System.in);
  return scanner.nextInt();
 }

}

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Two different ways of writing logic to find biggest of 2 numbers.

2. Biggest of 2 numbers.

package com.thebeautifuljava.simpleprograms;

public class BiggestOfTwoNumbers {
 public static void main(String[] args) {
  System.out.println("BIGGEST OF 2 NUMBERS IS:" + findBiggest(100, 65));
  System.out.println("BIGGEST OF 2 NUMBERS IS (Ternary):"
    + findBiggestTernary(100, 65));
 }

 // method 1
 private static int findBiggest(int first, int second) {
  if (first > second)
   return first;
  return second;
 }

 // method 2
 private static int findBiggestTernary(int first, int second) {
  return (first > second) ? first : second;
 }

}

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Best way to re-use CommonUtils class.
3. Biggest of 2 numbers by inputting through keyboard.

package com.thebeautifuljava.simpleprograms;

import com.thebeautifuljava.utils.CommonUtils;

public class BiggestOfTwoNumbersRead {
 public static void main(String[] args) {

  System.out.println("ENTER FIRST NUMBER :");
  int first = CommonUtils.readFromKeyBoard();

  System.out.println("ENTER SECOND NUMBER :");
  int second = CommonUtils.readFromKeyBoard();

  System.out.println("BIGGEST OF 2 NUMBERS IS:" + findBiggest(first, second));
 }

 private static int findBiggest(int first, int second) {
  if (first > second)
   return first;
  return second;
 }

}

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Best way to re-use CommonUtils class.
4. Calculate factorial of a given number.

package com.thebeautifuljava.simpleprograms;

import com.thebeautifuljava.utils.CommonUtils;

public class Factorial {

 public static void main(String[] args) {

  System.out.println("ENTER NUMBER :");
  int number = CommonUtils.readFromKeyBoard();

  System.out.println("Factorial :" + getFactorial(number));
 }

 private static long getFactorial(int number) {
  // TODO Auto-generated method stub

  int factorial = 1;

  for (int i = 1; i <= number; i++) {
   factorial = factorial * i;
  }

  return factorial;

 }

}

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5. Print fibonacci series.

package com.thebeautifuljava.simpleprograms;

import com.thebeautifuljava.utils.CommonUtils;

public class FibonacciSeries {

 public static void main(String args[]) {

  System.out.println("ENTER LIMIT :");
  int limit = CommonUtils.readFromKeyBoard();

  printNumbers(limit);
 }

 private static void printNumbers(int limit) {

  int first = 0, second = 1;

  // prints 0 and 1
  System.out.println("FIBONACCI SERIES:");
  System.out.print(first + " " + second);

  for (int i = 2; i < limit; i++) {

   int next = first + second;
   System.out.print(" " + next);

   first = second;
   second = next;
  }
 }
}

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6. Check whether number is prime.

package com.thebeautifuljava.simpleprograms;

import com.thebeautifuljava.utils.CommonUtils;

public class PrimeNumberCheck {

 public static void main(String args[]) {

  System.out.println("PLEASE ENTER A NUMBER :");
  int number = CommonUtils.readFromKeyBoard();

  // validation check for negative numbers and zero
  if (number <= 0) {
   throw new IllegalArgumentException("PLEASE ENTER A POSITIVE NUMBER");
  }

  if (number == 1) {
  throw new IllegalArgumentException("NUMBER IS NOT PRIME");
  }

  System.out.println("IS PRIME NUMBER :" + isPrime(number));
 }

 private static boolean isPrime(int number) {

  // If number is 50, then sqrt(50) will be 7.071...
  int sqrt = (int) Math.sqrt(number) + 1;

  for (int i = 2; i < sqrt; i++) {
   // check for divisibility of a number
   if (number % i == 0) {
    return false;
   }
  }

  return true;
 }

}

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