CODEWITHSUNDEEP
java
Chris Valenzuela
Chris Valenzuela

Reputation: 39

asks the user for an angle in degrees between 0 and 180

My program accepts any number that I input even 1 million >.< but I only wanted to ask the user to input an angle in degrees between 0 to 180 and outputs the sine, cosine and tangent of that angle

here is my program :

import java.util.Scanner;
import java.text.DecimalFormat;
public class Mathematics
{
  public static void main(String args[])
  {

    System.out.println("Enter an Angle ");
    Scanner data = new Scanner(System.in);
    int x;
    x=data.nextInt();

    double sinx = Math.sin( Math.toRadians(x) );
    double cosx = Math.cos( Math.toRadians(x) );
    double tanx = Math.tan( Math.toRadians(x) );

    DecimalFormat format = new DecimalFormat("0.##");
    System.out.println("Sine of a circle is  " + format.format(sinx));
    System.out.println("cosine of a circle is  " + format.format(cosx));
    System.out.println("tangent of a circle is  " + format.format(tanx));

  }
}

Upvotes: 0

Views: 2441

Answers (3)

tucuxi
tucuxi

Reputation: 17945

Put the question in a loop. When the user enters a value that is outside your range, print an error message and request a different value. When the entered value is OK, then you can exit the loop. It is better to use a function to make things more readable:

public static int askForInt(String question, String error, int min, int max) {
    while (true) {
       System.out.print(question + " (an integer between " + min + " and " + max + "): ");
       int read = new Scanner(System.in).nextInt();
       if (read >= min && read <= max) {
          return read;
       } else {
          System.out.println(error + " " + in + " is not a valid input. Try again.");
       }
    }
}

Call like this: x = askForInt("The angle", "Invalid angle", 0, 180);

Upvotes: 1

ose
ose

Reputation: 4075

Put this code after x=data.nextInt();

if( x < 0 || x > 180 )
{
    throw new Exception("You have entered an invalid value");
}

This will cause your program to crash if the user inputs a number outside the range [0, 180]. If you wish to allow the user to try again, you would need to put the program into a loop, like so:

do
{
    System.out.print("Enter a value in [0, 180]: ");
    x = data.nextInt();
} while(x < 0 || x > 180);

This loop will continue until the user enters the desired values.

Upvotes: 3

kenota
kenota

Reputation: 5662

Instead of

x = data.nextInt();

write

do {
    x = data.nextInt();
    if (x < 0 || x > 180) {
        System.out.println("Please enter number between 0-180");
    }
} while (x < 0 || x > 180);

Upvotes: 2

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