Question

Re-write following if-else-if statements as Switch statement. Your final code should result in the same output as the original code below.

if (selection == 10)

System.out.println("You selected 10.");

else if (selection == 20)

System.out.println("You selected 20.");

else if (selection == 30)

System.out.println("You selected 30.");

else if (selection == 40)

System.out.println("You selected 40.");

else System.out.println("Not good with numbers, eh?");

2.

Write a Constructor for the TrafficLight class that sets stopLight value to “red”, waitLight to “yellow” and goLight to “green”?

Answer 1

Hey There,

- I understood your question and I have given the answer to the best of my knowledge.

- I have also put comments in the code so that you can also understand what I did in the code.

- If you need further explanations then do let me know in the comments box I will be more than happy to help you.

Answer:

Question 1:

- Below I have provided the switch case implementation of the given if else-if code.

- While using the switch case we use break after all the cases so that once the switch case matches it does not go to the next case.

- Switch Implementation code:

switch(selection){
    case 10: System.out.println("You selected 10.");
    break;
    case 20: System.out.println("You selected 20.");
    break;
    case 30: System.out.println("You selected 30.");
    break;
    case 40: System.out.println("You selected 40.");
    break;
    default: System.out.println("Not good with numbers, eh?");
}

Question 2:

- Constructor is a block of codes similar to the method. It is called when an instance of the class is created. It is mainly used to initialize the object.

- The name of constructor is same as the class name.

- Below I have provided the given constructor code as asked in the question:

// Declaring variables
String stopLight;
String waitLight;
String goLight;

// Defining constructor
TrafficLight(){
    stopLight = "red";
    waitLight = "yellow";
    goLight = "green";
}

- Below here I have also provided the whole code so that you can understand well.

- Here I have also used the display method that will print the values of stopLight, waitLight and goLight. By this we can confirm that our code is working correctly.

public class TrafficLight
{
    // Declaring variables
    String stopLight;
    String waitLight;
    String goLight;
    
    // Defining constructor
    TrafficLight(){
        stopLight = "red";
        waitLight = "yellow";
        goLight = "green";
    }
    
    // This function will print values of stopLight, waitLight and goLight
    void display(){
        System.out.println(stopLight);
                System.out.println(waitLight);
                System.out.println(goLight);
    }
    // main method
        public static void main(String[] args) {
            // Creating object of TrafficLight class
                TrafficLight t1 = new TrafficLight();
                
                // Calling display method
                t1.display();
        }
}

Screenshot of it working correctly:

Hope it helps:)