REVIEW

a) 

1  8  8
-48  8  8

b) 

a. public static int method(int b, int a)

b. c = method(a, b); AND a = method(b, a);

c. 

public static int method(int b, int a) {
    int d;

    d = a * b - b * b;
    return d + b;
}

c) 

import java.util.Scanner;//Scanner
public class CountOccurrences {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.print("Enter a String: ");
        String temp = sc.nextLine().toLowerCase();
        int count = 0;
        for(char c='a'; c<='z'; c++) {// iterate for each lower case letter
            count = countOccurrences(temp, c);// count number of times lower case letter appears
            if(count>0) System.out.println(c + " appears " + count + " times");// if it appears, output how many times
        }
    }

    // iterate through the String and compare each lowercase version of the letter at that index to c, returning the count
    public static int countOccurrences(String temp, char c) {
        int count = 0;
        for(int i=0; i<temp.length(); i++) {
            if(c==temp.charAt(i)) count++;
        }
        return count;
    }
}

d)

public static boolean isDivisible(double n, double m) {
    return (n % m == 0);
}

e) 

/**
 * Checks if the given three sides form a valid triangle.
 * @param side1 the length of the first side of the triangle
 * @param side2 the length of the second side of the triangle
 * @param side3 the length of the third side of the triangle
 * @return true if the sides can form a valid triangle, false otherwise 
 */
public static boolean isTriangle(int side1, int side2, int side3) {
    boolean isPositive = (side1 > 0) && (side2 > 0) && (side3 > 0);
    return (isPositive && (side1 + side2 > side3) && (side1 + side3 > side2) && (side2 + side3 > side1));
}

f) 

true
true
ping!
pong!

g) 

public static double calculateVolumeOfSphere(double radius) {
    return (4.0/3.0) * Math.PI * Math.pow(radius, 3);
}

public static double calculateSurfaceAreaOfSphere(double radius) {
    return 4 * Math.PI * Math.pow(radius, 2);
}

public static boolean isSphereLarge(double radius) {
    return calculateVolumeOfSphere(radius) > 1000;
}

public static void main(String [] args) {
    double radius = 5.0;
    double volume = calculateVolumeOfSphere(radius);
    double surfaceArea = calculateSurfaceAreaOfSphere(radius);
    boolean isLarge = isSphereLarge(radius);

    System.out.println("Volume of the sphere: " + volume + " cubic units");
    System.out.println("Surface area of the sphere: " + surfaceArea + " square units");
    System.out.println("Is the sphere large: " + isLarge);
}

LAB 4 TO BE DISCUSSED IN CLASS

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Week 11

1) 

Value: 1
Value: 4
Value: 7
Value: 10

2) 

1 : 0.5
2 : 2.0
3 : 4.5
4 : 8.0
5 : 12.5

3) 

public class RandomIntegersCounter {
    public static void main(String [] args) {
        final int SIZE = 20;
        int max = 100;
        int min = 1;
        int[] randomNumbers = new int[SIZE];

        for (int i = 0; i < SIZE; i++) {
            int rand = (int) (Math.random() * (max - min) + min);
            randomNumbers[i] = rand;
        }

        System.out.println("Generated random numbers:");
        System.out.print("{");
        for (int i = 0; i < randomNumbers.length; i++) {
            System.out.print(randomNumbers[i]);
            if(i < randomNumbers.length - 1)
                System.out.print(", ");
        }
        System.out.println("}");
        System.out.println();

        System.out.println("Even numbers count: " + countEvenNumbers(randomNumbers));
        System.out.println("Odd numbers count: " + countOddNumbers(randomNumbers));
        System.out.println("Multiples of 5 count: " + countMultiplesOf5(randomNumbers));
    }


    public static int countEvenNumbers(int [] arr) {
        int count = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] % 2 == 0) {
                count++;
            }
        }
        return count;
    }

    public static int countOddNumbers(int [] arr) {
        int count = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] % 2 != 0) {
                count++;
            }
        }
        return count;
    }

    public static int countMultiplesOf5(int [] arr) {
        int count = 0;
        for (int i = 0; i < arr.length; i++) {
            if (arr[i] % 5 == 0) {
                count++;
            }
        }
        return count;
    }
}

4)

for (int i = 0; i < (arr.length+1) / 2; i++) {
      int temp = arr[i];
      arr[i] = arr[arr.length-i-1];
      arr[arr.length-i-1] = temp;
}