Java Intermediate: 6/24/2021

Main.java

package com.javafx.test;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        selectionSort();
        interest();
        randomNumbers();
        power();
    }
    public static void selectionSort(){
        int[] list = new int[10];
        for (int i =0; i < list.length; i++){
            list[i] = (int) (Math.random()*100)+1;
        }
        //print the unsorted array
        for (int n : list) {
            System.out.print(n + " ");
        }
        System.out.println(); // move cursor to next line

        // goes up to index list.length - 1
        // because you don't need to check last element
        // since it will be sorted already
        for (int i = 0; i < list.length - 1; i++) {
            int min = list[i];
            int minIndex = i;

            // find the current smallest element
            for (int j = i + 1; j < list.length; j++) {
                if (list[j] < min) {
                    min = list[j];
                    minIndex = j;
                }
            }

            // swap it with whatever is in the
            // first position of unsorted array if needed
            if (minIndex != i) {
                int temp = list[i];
                list[i] = min;
                list[minIndex] = temp;
            }
        }

        // print the sorted array
        for (int n : list) {
            System.out.print(n + " ");
        }
        System.out.println(); // move cursor to next line
    }
    public static void interest(){
        Scanner input = new Scanner(System.in);

        // prompt user for principal, rate, and time
        System.out.print("Enter the principal amount: $");
        double principal = input.nextDouble();
        System.out.print("Enter the annual interest rate (in percentage points): ");
        double rate = input.nextDouble()/100;
        System.out.print("Enter the period of time (in years): ");
        int time = input.nextInt();

        input.close();

        // calculate the final amount using A = Pe^(rt)
        double finalAmount = principal * Math.exp(rate * time);

        // display the final amount (2 decimals precision)
        System.out.printf("The final amount is $%,.2f\n", finalAmount); // added newline to move cursor to next line
    }
    public static void randomNumbers() {
        int[][] numbers = new int[4][6]; // create 4x6 array
        int sum = 0; // sum of all elements in array
        int max = Integer.MIN_VALUE; // max element in array
        int min = Integer.MAX_VALUE; // min element in array

        // iterate through each element in a
        for (int row = 0; row < 4; row++) {
            for (int col = 0; col < 6; col++) {
                // generate a random number from 7 to 77
                // and store it in the array
                numbers[row][col] = randInt(7, 77);

                // print that element
                System.out.print(numbers[row][col] + "\t");

                // keep a running total of all elements
                sum += numbers[row][col];

                // update min or max as needed
                if (numbers[row][col] < min) {
                    min = numbers[row][col];
                }

                if (numbers[row][col] > max) {
                    max = numbers[row][col];
                }
            }
            System.out.println(); // move to next row
        }

        // display the sum of all elements
        // and the max and min element
        System.out.println("Sum: " + sum);
        System.out.println("Max: " + max);
        System.out.println("Min: " + min);
    }

    /**
     * Returns a random integer
     * in the range [min, max]
     * @param min  minimum random integer
     * @param max  maximum random integer
     * @return a random integer in the range [min, max]
     */
    public static int randInt(int min, int max) {
        return min + (int) (Math.random() * ((max - min) + 1));
    }
    public static void power(){
        // create a 5x4 array
        int[][] array = new int[5][4];

        for (int power = 2; power < 7; power++) {
            for (int base = 2; base < 6; base++) {
                // assign the correct element based on the pattern
                array[power - 2][base - 2] = (int) (Math.pow(base, power));

                // print the current element
                System.out.print(array[power - 2][base - 2] + "\t\t");
            }
            System.out.println(); // move to next row
        }
    }
}