Question

CIT-111 Homework #4, Part A                                                                    Chapter 4, problem #7 (pages 254-255)

A breakdown of the problem is as follows:

• Class name:                        Temperature
  
• Instance variables:           temp (double) and tempScale (char; either ‘C’ or ‘F’)
  
• Constructor methods:    Temperature() – sets temp to 0 Celsius
  
                                                  Temperature(double initialTemp) – sets temp
  
                                                  Temperature(char tempType) – sets tempScale to ‘C’ or ‘F’)
  
                                                  Temperature(double initialTemp, char tempType) --
                                                                  sets temp and tempScale to ‘C’ or ‘F’)
  
• Accessor methods:          getTemp – returns value of temp for the object
                                                  getTempScale– returns temperature scale (‘C’ or ‘F’)
  
• Mutator methods:           setTemp – sets the value of temp
                                                  setScale – sets the value of tempScale
                                                  setTempSystem – sets both the value of temp and tempScale
  
• Comparison methods:   equals – determines if argument is equal to current temperature
                                                  greaters—determines if argument is greater than current temperature
                                                  lessers—determines if argument is less than current temperature
  
  Allow for conversion using temperature formulas prior to doing comparison.
  DegreesC = 5 / 9 * (degreesF – 32)            DegreesF = (9/5 * (degreesC) ) + 32
  
• Additional method:         tostring – returns a string that is representative of the object

Write a driver program(s) that tests all methods and constructors and at least test

• 0.0 C      =             32.0 F
• -40.0 C =             -40.0 F
• 100.0 C =             212.0 F

two files (Temperature.java and TemperatureDemo.java. Both files must compile without errors.
                                               
                                               

Answer 1

Here is the completed code for this problem. Comments are included, go through it, learn how things work and let me know if you have any doubts or if you need anything to change. If you are satisfied with the solution, please rate the answer. Thanks

// Temperature.java

public class Temperature {

                // attributes

                private double temp;

                private char tempScale;

                // constructor to initialize temperature to 0 and scale to 'C'

                public Temperature() {

                                temp = 0;

                                tempScale = 'C';

                }

                // constructor to initialize a temmperature in 'C'

                public Temperature(double initialTemp) {

                                temp = initialTemp;

                                tempScale = 'C';

                }

                // constructor to initialize a '0' temperature in tempType.

                // throws exception if tempType is not 'C' or 'F'

                public Temperature(char tempType) {

                                temp = 0;

                                if (!isValidScale(tempType)) {

                                               throw new RuntimeException("Invalid temperature type.");

                                }

                                this.tempScale = tempType;

                }

                // constructor to initialize a temperature in tempType.

                // throws exception if tempType is not 'C' or 'F'

                public Temperature(double initialTemp, char tempType) {

                                temp = initialTemp;

                                if (!isValidScale(tempType)) {

                                               throw new RuntimeException("Invalid temperature type.");

                                }

                                this.tempScale = tempType;

                }

                // returns the temperature

                public double getTemp() {

                                return temp;

                }

                // returns the scale

                public char getTempScale() {

                                return tempScale;

                }

                // sets the temperature

                public void setTemp(double temp) {

                                this.temp = temp;

                }

                // method to set the scale to a new scale. the temperature in old scale will

                // be converted to the new scale if necessary.throws exception if tempType

                // is not 'C' or 'F'

                public void setScale(char newScale) {

                                if (!isValidScale(newScale)) {

                                               throw new RuntimeException("Invalid temperature type.");

                                }

                                // converting temperature in C to F if previous scale is C and new scale

                                // is F

                                if (tempScale == 'C' && newScale == 'F') {

                                               temp = temp * (9.0 / 5.0) + 32;

                                }

                                // converting temperature in F to C if previous scale is F and new scale

                                // is C

                                else if (tempScale == 'F' && newScale == 'C') {

                                               temp = (temp - 32) / (9.0 / 5.0);

                                }

                                // setting new scale

                                tempScale = newScale;

                }

                // method to set new temperature and scale.

                public void setTempSystem(double temp, char tempScale) {

                                if (!isValidScale(tempScale)) {

                                               throw new RuntimeException("Invalid temperature type.");

                                }

                                this.temp = temp;

                                this.tempScale = tempScale;

                }

                // helper method to check if the scale is valid or not

                private boolean isValidScale(char c) {

                                if (c == 'C' || c == 'F') {

                                               return true;

                                }

                                return false;

                }

                @Override

                public boolean equals(Object obj) {

                                if (obj instanceof Temperature) {

                                               // safe type casting

                                               Temperature other = (Temperature) obj;

                                               // creating a new Temperature object using other object's values

                                               Temperature temperature = new Temperature(other.temp,

                                                                               other.tempScale);

                                               // converting other temperature to this scale so that this scale and

                                               // the other scales will be same and we can compare the temperatures

                                               temperature.setScale(this.tempScale);

                                               // checking if both temperatures are same

                                               return this.temp == temperature.temp;

                                }

                                return false;

                }

                // returns true if this temperature > other

                public boolean greaters(Temperature other) {

                                // creating a new Temperature object using other object's values

                                Temperature temperature = new Temperature(other.temp, other.tempScale);

                                // converting other temperature to this scale so that this scale and

                                // the other scales will be same and we can compare the temperatures

                                temperature.setScale(this.tempScale);

                                return this.temp > temperature.temp;

                }

                // returns true if this temperature < other

                public boolean lessers(Temperature other) {

                                Temperature temperature = new Temperature(other.temp, other.tempScale);

                                temperature.setScale(this.tempScale);

                                return this.temp < temperature.temp;

                }

                @Override

                public String toString() {

                                return temp + " " + tempScale;

                }

}

// TemperatureDemo.java

public class TemperatureDemo {

                public static void main(String[] args) {

                                // creating objects and testing all methods of Temperature class

                                Temperature temp1 = new Temperature();

                                System.out.println("temp1: " + temp1);

                                Temperature temp2 = new Temperature(32, 'F');

                                System.out.println("temp2: " + temp2);

                                System.out.println("temp1 = temp2: " + temp1.equals(temp2));

                                System.out.println("temp1 < temp2: " + temp1.lessers(temp2));

                                System.out.println("temp1 > temp2: " + temp1.greaters(temp2));

                                Temperature temp3 = new Temperature();

                                System.out.println("temp3: " + temp3);

                                System.out.println("temp3 scale: " + temp3.getTempScale());

                                temp3.setTempSystem(-40, 'C');

                                System.out.println("Converting temp3 to F");

                                temp3.setScale('F');

                                System.out.println("temp3: " + temp3);

                                System.out.println("0.0 C = 32.0 F: "

                                                               + new Temperature(0, 'C').equals(new Temperature(32.0, 'F')));

                                System.out

                                                               .println("-40.0 C = -40.0 F: "

                                                                                               + new Temperature(-40, 'C').equals(new Temperature(

                                                                                                                              -40.0, 'F')));

                                System.out.println("100.0 C = 212.0 F: "

                                                               + new Temperature(100, 'C').equals(new Temperature(212, 'F')));

                }

}

/*OUTPUT*/

temp1: 0.0 C

temp2: 32.0 F

temp1 = temp2: true

temp1 < temp2: false

temp1 > temp2: false

temp3: 0.0 C

temp3 scale: C

Converting temp3 to F

temp3: -40.0 F

0.0 C = 32.0 F: true

-40.0 C = -40.0 F: true

100.0 C = 212.0 F: true