Question

#1 Write a java program which calculates the area of either a Triangle or a Rectangle. Use Scanner to take an input field to tell you if the area to be calculated is for a Triangle or is for a Rectangle. Depending on that input - the program must call either the Triangle method or the Rectangle method. Each of those methods must receive 2 input fields from the user - one for base and one for height in order to calculate the area and then to print that area and the height and base from inside the method.

Answer 1

Program File

AreaCalculator.java

// import the scanner class to read input from stdin
import java.util.Scanner;

class AreaCalculator {
public static double triangleArea(double length, double base){

// area of triangle is 0.5 * length * base
return 0.5 * length * base;

}

public static double rectangleArea(double length, double width)
{
// area of rectangle is length * width
return length * width;
}

public static void main(String[] args) {

int userChoice;
double length;

// Intro message
System.out.println("***** Welcome to area calculator *****");

// scanner object to read input from stdin
Scanner scan = new Scanner(System.in);

System.out.println("Choose for what you want to calculate area\n1. Triangle\n2. Rectangle\n0. Exit");

// read user choice
userChoice = scan.nextInt();

switch(userChoice){
case 0:
System.exit(0);
break;

// When triangle is selected
case 1:

// read length from stdin
System.out.print("Enter the height of the triangle : ");
length = scan.nextDouble();

// read base from stdin
System.out.print("Enter the base of the triangle : ");
double base = scan.nextDouble();

// calculate area and print to stdout
System.out.println("The area of triangle is : " + triangleArea(length, base));

break;
  
// when rectangle is selected
case 2:

// read length from stdin
System.out.print("Enter the height of the rectangle : ");
length = scan.nextDouble();

// read width from stdin
System.out.print("Enter the width of the rectangle : ");
double width = scan.nextDouble();

// calculate area and print to stdout
System.out.println("The area of rectangle is : " + rectangleArea(length, width));
break;
  
default:
System.out.println("Invalid Entry!");
}
  
}

}

Output

***** Welcome to area calculator *****
Choose for what you want to calculate area
1. Triangle
2. Rectangle
0. Exit
1
Enter the height of the triangle : 10
Enter the base of the triangle : 10
The area of triangle is : 50.0

***** Welcome to area calculator *****
Choose for what you want to calculate area
1. Triangle
2. Rectangle
0. Exit
2
Enter the height of the rectangle : 10
Enter the width of the rectangle : 10
The area of rectangle is : 100.0

Hope this helps!

Please let me know if any changes needed.

Thank you!

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