AP CS A - Chapter 5 Solutions (100pts)

FloatCheck.java

public class FloatCheck {

    float one, two;

    public FloatCheck(float one, float two) {
        this.one = one;
        this.two = two;
    }

    public boolean roundToTwoDec() {

        double oneVal = (double) Math.round(one * 100) / 100.0;
        double twoVal = (double) Math.round(two * 100) / 100.0;

        if (oneVal == twoVal) {
            return true;
        } else {
            return false;
        }
    }

    public boolean differ() {
        double diff = (double) Math.abs(one - two);
        if (diff < 0.01) {
            return true;
        }
        return false;
    }


}

FloatCheckTester.java

import java.util.Scanner;

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

        Scanner s = new Scanner(System.in);
        float one, two;
        System.out.println("Enter two floating-point numbers:");
        one = s.nextFloat();
        two = s.nextFloat();

        FloatCheck fc = new FloatCheck(one, two);

        if (fc.roundToTwoDec()) {
            System.out.println("They are the same when rounded to two decimal places.");
        } else {
            System.out.println("They are different when rounded to two decimal places.");
        }

        if (fc.differ()) {
            System.out.println("They differ by less than 0.01");
        } else {
            System.out.println("They do not differ by less than 0.01");
        }


    }
}

Grade.java

import java.util.ArrayList;
import java.util.HashMap;

public class Grade {

    private HashMap<String, Double> gradeDict = new HashMap<String, Double>();

    String grade;

    public Grade(String grade) {
        this.grade = grade;
        setupDict();
    }

    public double getNumericGrade() {

        double gradeVal = Double.NaN;

        try {
            gradeVal = gradeDict.get(this.grade);
        } catch(NullPointerException e){
            System.out.println("Invalid Input.");
            System.exit(1);
        }

        return 4.0 - gradeVal;

    }

    private void setupDict() {
        gradeDict.put("A+", 0.3 * 0);
        gradeDict.put("A-", 0.3 * 1);
        gradeDict.put("B+", 0.3 * 2);
        gradeDict.put("B-", 0.3 * 3);
        gradeDict.put("C+", 0.3 * 4);
        gradeDict.put("C-", 0.3 * 5);
        gradeDict.put("D+", 0.3 * 6);
        gradeDict.put("D-", 0.3 * 7);
        gradeDict.put("F", 0.3 * 8);
    }

}

GradeTester.java

import java.util.Scanner;

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

        String grade;

        Scanner input = new Scanner(System.in);
        System.out.println("Enter a letter grade:");

        grade = input.nextLine();

        Grade g = new Grade(grade);

        System.out.println("Numeric value: " + g.getNumericGrade());

    }
}

LexicographicOrder.java

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;

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

        ArrayList<String> words = new ArrayList<String>();
        Scanner input = new Scanner(System.in);
        String[] alphabet = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "l", "m", "n", "o", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z"};


        System.out.println("Please enter three strings:");

        words.add(input.nextLine());
        words.add(input.nextLine());
        words.add(input.nextLine());

        Collections.sort(words);

        for(String s : words){
            System.out.println(s);
        }

    }
}

Paycheck.java

public class Paycheck {

    private double wage, hours;

    public Paycheck(double wage, double hours) {
        this.wage = wage;
        this.hours = hours;
    }

    public double calculatePay() {

        if (40 >= hours) {
            return wage *= hours;
        }

        return wage = (wage * hours) * 1.5;

    }

}

PaycheckTester.java

import java.util.Scanner;

public class PaycheckTester {
    public static void main(String[] args) {
        double wage, hours;

        Scanner s = new Scanner(System.in);
        System.out.println("Hours Worked (ex: 11, 16.5, etc): ");
        hours = s.nextDouble();
        System.out.println("Wage (ex: 9.55): ");
        wage = s.nextDouble();

        Paycheck p = new Paycheck(wage, hours);

        System.out.println("You're paycheck is: $" + p.calculatePay());

    }
}

Sort.java

public class Sort {

    float a, b, c;
    float one, two, three;

    public Sort(float a, float b, float c) {

        this.a = a;
        this.b = b;
        this.c = c;

    }

    public String getSortedValues() {

        if (a > b && a > c) {
            System.out.println(a + "is the biggest");
            one = a;
            if (b > c) {
                two = b;
                three = c;
            } else {
                two = c;
                three = b;
            }
        } else if(b > a && b > c) {
            one = b;
            if (a > c) {
                two = a;
                three = c;
            } else {
                two = c;
                three = a;
            }
        } else if (c > a && c > b) {
            one = c;
            if (b > a) {
                two = b;
                three = a;
            } else {
                two = a;
                three = b;
            }
        }

        return "\n" + Float.toString(three) + "\n" + Float.toString(two) + "\n" + Float.toString(one) + "\n";
    }

}

SortTester.java

import java.util.Scanner;

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

        float a, b, c;

        String aString = "hello";
        String bString = "hello";

        Scanner input = new Scanner(System.in);

        System.out.println("Please enter three numbers");

        a = input.nextFloat();
        b = input.nextFloat();
        c = input.nextFloat();

        Sort s = new Sort(a, b, c);

        System.out.println("The inputs sorted order are: " + s.getSortedValues());

    }
}

UnitConverter.java

import java.util.HashMap;

public class UnitConverter {

    private String from, to;
    private double value;
    private HashMap<String, Double> conversionDict = new HashMap<String, Double>();

    public UnitConverter(String from, String to, double value) {
        this.from = from;
        this.to = to;
        this.value = value;
        init();
    }

    public double getConversion() {

        String query = this.from + "_to_" + this.to;

        return value * conversionDict.get(query);

    }

    private void init() {
        conversionDict.put("in_to_ft", 0.083);
        conversionDict.put("in_to_mi", 1.6E-05);
        conversionDict.put("in_to_mm", 25.4);
        conversionDict.put("in_to_cm", 2.54);
        conversionDict.put("in_to_m", 0.025);
        conversionDict.put("in_to_km", 2.5E-05);

        conversionDict.put("ft_to_in", 12.0);
        conversionDict.put("ft_to_mi", 0.00019);
        conversionDict.put("ft_to_mm", 304.8);
        conversionDict.put("ft_to_cm", 30.48);
        conversionDict.put("ft_to_m", 0.3);
        conversionDict.put("ft_to_km", 0.0003);

        conversionDict.put("mi_to_in", 63360.0);
        conversionDict.put("mi_to_ft", 5280.0);
        conversionDict.put("mi_to_mm", 1.60934E+06);
        conversionDict.put("mi_to_cm", 160934.0);
        conversionDict.put("mi_to_m", 1609.34);
        conversionDict.put("mi_to_km", 1.61);

        conversionDict.put("mm_to_in", 0.039);
        conversionDict.put("mm_to_mi", 6.2E-07);
        conversionDict.put("mm_to_ft", 0.0033);
        conversionDict.put("mm_to_cm", 0.1);
        conversionDict.put("mm_to_m", 0.1);
        conversionDict.put("mm_to_km", 1E-06);


        conversionDict.put("cm_to_in", 0.39);
        conversionDict.put("cm_to_mi", 6.2E-06);
        conversionDict.put("cm_to_mm", 10.0);
        conversionDict.put("cm_to_ft", 0.033);
        conversionDict.put("cm_to_m", 0.01);
        conversionDict.put("cm_to_km", 1E-05);

        conversionDict.put("m_to_in", 39.37);
        conversionDict.put("m_to_mi", 0.00062);
        conversionDict.put("m_to_mm", 1000.0);
        conversionDict.put("m_to_ft", 3.28084);
        conversionDict.put("m_to_cm", 100.0000032);
        conversionDict.put("m_to_km", 0.001000000032);

        conversionDict.put("km_to_in", 39370.08);
        conversionDict.put("km_to_mi", 0.62137121212121);
        conversionDict.put("km_to_mm", 1000000.0319999966305);
        conversionDict.put("km_to_ft", 3280.8399999999887768);
        conversionDict.put("km_to_cm", 100000.00319999965723);
        conversionDict.put("km_to_m", 1000.0000319999966223);
    }
}

UnitConverterTester.java

import java.util.Scanner;

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

        String from, to;
        double value;

        Scanner s = new Scanner(System.in);
        System.out.println("Convert from:");
        from = s.nextLine().toLowerCase();
        System.out.println("Convert to:");
        to = s.nextLine().toLowerCase();

        System.out.println("Value:");
        value = s.nextDouble();

        UnitConverter u = new UnitConverter(from, to, value);

        System.out.println(value + " " + from + " = " + u.getConversion() + " " + to);

    }
}

Year.java

public class Year {

    public static boolean isLeapYear(int year) {
        if (year % 4 != 0) {
            return false;
        } else if (year % 400 == 0) {
            return true;
        } else if (year % 100 == 0) {
            return false;
        } else {
            return true;
        }
    }

}

YearTester.java

import java.util.Scanner;

public class YearTester {
    public static void main(String[] args) {
        Scanner s = new Scanner(System.in);
        System.out.println("Enter Year:");
        int year = s.nextInt();
        System.out.print(new Year().isLeapYear(year));
    }
}

YesNoChecker.java

import java.util.Scanner;

public class YesNoChecker {

    public  static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        String response;

        System.out.println("Do you want to continue?");

        response = input.nextLine();

        handleResponse(response);

    }

    public static void handleResponse(String response) {

        String[] yesRes = {"Y", "Yes", "OK", "Sure", "Why not?"};
        String[] noRes = {"N", "No"};
        String result = null;

        for (int i=0; i< yesRes.length; i++) {
            if (yesRes[i].toLowerCase().indexOf(response.toLowerCase()) != -1) {
                result = "y";
            }
        }

        for (int i=0; i< noRes.length; i++) {
            if (noRes[i].toLowerCase().indexOf(response.toLowerCase()) != -1) {
                result = "n";
            }
        }

        if (result != null) {
            if (result == "y") {
                System.out.println("OK");
                System.exit(1);
            } else {
                System.out.println("Terminating");
                System.exit(1);
            }

        } else {
            System.out.println("Bad Input");
            System.exit(1);
        }

    }

}