Answer:
Here is the complete program:
import javax.swing.JOptionPane; //to use GUI in JAVA application
import java.util.Scanner; //to take input from user at console
public class Main {
public static void main(String[] args) { //start of main function body
String num1, num2,num3; //declare three variables to store strings of numbers for input dialog
double number1, number2, number3, sum,product; //declare three double type variables to hold the real numbers
num1 = JOptionPane.showInputDialog("num1"); //shows a dialog box prompting user to enter value of first number i.e. num1
number1 = Double.parseDouble(num1); //scans and reads the value of first input number i.e. number1
num2 = JOptionPane.showInputDialog("num2"); //shows a dialog box prompting user to enter value of second number i.e. num2
number2 = Double.parseDouble(num2); //reads number2
num3 = JOptionPane.showInputDialog("num3"); //shows a dialog box prompting user to enter value of third number i.e. num3
number3 = Double.parseDouble(num3); //reads number3
if(number1>0&& number2>0 && number3>0){ //checks if all three numbers are positive
sum = number1 + number2+ number3; //displays the sum by adding all three positive numbers
JOptionPane.showMessageDialog(null, "the sum is : " + sum , "Results", JOptionPane.PLAIN_MESSAGE ); } // displays the result of sum in a message dialog box
if(number1<0 && number2>0 && number3>0) { //checks if number2 and number3 are positive
product = number2*number3; //computes product
JOptionPane.showMessageDialog(null, "the product is : " + product , "Results", JOptionPane.PLAIN_MESSAGE ); } //displays the result
else if (number2<0&&number1>0&&number3>0){ //checks if number1 and number3 are positive
product = number1*number3; //computes product
JOptionPane.showMessageDialog(null, "the product is : " + product , "Results", JOptionPane.PLAIN_MESSAGE ); } //displays the result
else if (number3<0 && number1>0 && number2>0) { //checks if number1 and number2 are positive
product = number1*number2; //computes product of 2 positive numbers
JOptionPane.showMessageDialog(null, "the product is : " + product , "Results", JOptionPane.PLAIN_MESSAGE ); } //displays the result
else { /.if all the numbers are positive.
/*However this part is optional. You can just use else part for above else if statement and exclude this else part. In this way the product of all three positive numbers is not computed and product is only computed when only two numbers of the three are positive */
product = number1*number2*number3; //computes product of all three positive numbers
JOptionPane.showMessageDialog(null, "the product is : " + product , "Results", JOptionPane.PLAIN_MESSAGE ); } //displays the result
Scanner scan = new Scanner(System.in); //creates a Scanner class object
double value1 , value2, quotient; //declares variables to hold the values of two real numbers and the result of division of the two real numbers is stored in quotient variable
System.out.println("Enter the first real number: "); //prompts user to enter the value of first real number from the console
value1 = scan.nextDouble(); //reads the first number from user
System.out.println("Enter the second real number : "); //prompts user to enter the value of second real number from the console
value2 = scan.nextDouble(); //reads the second number from user
if(value1<0&&value2<0) { //checks if both the numbers are negative
quotient = value1/value2; //compute the quotient
JOptionPane.showMessageDialog(null, "the quotient is : " + quotient , "Results", JOptionPane.PLAIN_MESSAGE ); } //displays result
else //if both numbers are not negative
JOptionPane.showMessageDialog(null, "Both numbers are not negative" ); //displays this message in a dialog box
} }
Explanation:
In the above given code if you want to display the outputs in console then alter the following statements as follows:
if(number1>0&& number2>0 && number3>0){
sum = number1 + number2+ number3;
System.out.println("the sum is : " + sum); }
if(number1<0 && number2>0 && number3>0) {
product = number2*number3;
System.out.println("the product is : " + product); }
else if (number2<0&&number1>0&&number3>0){
product = number1*number3;
System.out.println("the product is : " + product); }
else if (number3<0 && number1>0 && number2>0) {
product = number1*number2;
System.out.println("the product is : " + product); }
else {
product = number1*number2*number3;
System.out.println("the product is : " + product); }
Scanner scan = new Scanner(System.in);
double value1 , value2, quotient;
System.out.println("Enter the first real number: ");
value1 = scan.nextDouble();
System.out.println("Enter the second real number : ");
value2 = scan.nextDouble();
if(value1<0&&value2<0) {
quotient = value1/value2;
System.out.println("the quotient is : " + quotient); }
else
System.out.println("Both numbers are not negative");
Notice that all the JOptionPane.showMessageDialog statement are changed with System.out.println which prints the results on the console.