Exercises with variables in Java

After the previous post about variables in java, in this one, I leave some exercises to practice what I explained then. This will be the way of acting for the rest of the Java topics, firstly I explain the topic and then, in the following post, I will propose a series of exercises and their solutions.

There are several possible solutions to solve the same problem, some more efficient than others. Here you can see a possible solution for each proposed exercise, which is not the only one possible.

Exercise 1

For now, we continue using the online compiler

In this exercise, we have to correct the errors of the following program so that it runs properly

public class AplicacionJava {
    public static void main(String[] args) {
        int a,b;c;
        a = 10; b=10;
        c =a+b;
        int cont;
        for (int i=a;i<c;i++){
            cont++;
            System.out.pritln ("counter: "cont);
            System.out.println(b+cont);
        }
    }
}

Solution

A possible solution is:

public class AplicacionJava {
    public static void main(String args[]) {
        int a,b,c;
        a = 10; b=10;
        c =a+b;
        int cont=0;
        for (int i=a;i<c;i++){
            cont++;
            System.out.println("counter: " + cont);
            System.out.println(b+cont);
        }
    }
}

Exercise 2

Develop a program with the following characteristics:

The program must have two variables of type double. The value of these variables is hardcoded, the first is 5 and the second is 7. And the program must display the following lines on the screen.

First value = <value stored in first variable>

Secondo value = <value stored in second variable>

Multiplication = <result of multiplying both values>

Division= <result of dividing both values>

Solution

A possible solution is:

public class MiPrograma {
    public static void main(String args[]) {
        double x=5;
        double y=7;
        System.out.println("First value = " + x);
        System.out.println("Second value = " + y);
        System.out.println("Multiplication = " + x*y);
        System.out.println("Division = " + x/y);
    }
}

If we execute this program, we would get:

First value = 5.0
Second value = 7.0
Multiplication = 35.0
Division = 0.7142857142857143

NOTE:

This post is part of the “Java” collection that reproduces the notes of the class that I teach on the subject at ESIC University. You can see the index of this collection here.

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