Basic Java Programs

BasicJavaCode.java

import java.util.Arrays;

/**
 * @author Vishal Rana
 * 
 */
public class BasicJavaCode {

    // Factorial
    public int factorial(int x) {
        int f = x == 0 ? 1 : x;
        while (x > 1) {
            f *= x - 1;
            x--;
        }
        return f;
    }

    // Factorial using recursion
    public int factUsingRecur(int x) {
        if (x == 0 || x == 1) {
            return 1;
        }
        return x * factUsingRecur(x - 1);
    }

    // Reverse a string
    public String reverseStr(String str) {
        StringBuffer revStr = new StringBuffer();
        for (int i = str.length() - 1; i >= 0; i--) {
            revStr.append(str.charAt(i));
        }
        return revStr.toString();
    }

    // Capitalize
    public String capitalize(String str) {
        StringBuffer capStr = new StringBuffer();
        for (int i = 0; i < str.length(); i++) {
            char c = str.charAt(i);
            if (i != 0 && str.charAt(i - 1) == ' ') {
                capStr.append(Character.toUpperCase(c));
            } else {
                capStr.append(c);
            }
        }
        return capStr.toString();
    }

    // Palindrome
    public boolean isPalindrome(String str) {
        int len = str.length();
        int i = 0;
        int j = len - 1;
        while (i <= len / 2) {
            if (str.charAt(i) != str.charAt(j)) {
                return false;
            }
            i++;
            j--;
        }
        return true;
    }

    // Anagram
    public boolean isAnagram(char[] word1, char[] word2) {
        Arrays.sort(word1);
        Arrays.sort(word2);
        if (String.valueOf(word1).equals(String.valueOf(word2))) {
            return true;
        }
        return false;
    }

    // LCM
    public int calcLCM(int x, int y) {
        int max = Math.max(x, y);
        int min = Math.min(x, y);
        int i = 1;
        while (true) {
            int z = max * i;
            if (z % min == 0) {
                return z;
            }
            i++;
        }
    }

}