Variable declared as double not working

[Biodun Adeniji]

import java.util.Scanner;
 public class GravityCalculator {

	public static void main(String[] args)
	{
		 Scanner input = new Scanner (System.in);
		
		 
		int a;  // Earth's gravity in m/s^2
		int v; // Initial velocity
		int x; // Initial position
		int t;
		double X;
		
					
		System.out.print("a: ");
		a = input.nextInt();
		
		System.out.print("v: ");
		v = input.nextInt();
		
		System.out.print("x: ");
		x = input.nextInt();
		
		System.out.print("t: ");
		t = input.nextInt();
		
		X = 0.5 * a * t * t + v * t + x; // x(t) = 0.5 × at^2 + vit + xi
			
				
		System.out.printf("The object's position is %d\n", X);
		}

I got error message when I tried to run the above program.  I discovered it has to do with variable X which is of double type.
How do I resolve this issue?

[Tapas Chand]

Welcome to the ranch  

What is the exact error when you are running your program?
In Java the error message is often very helpful to debug the issue.

[Biodun Adeniji]

Tapas Chand wrote:Welcome to the ranch  

What is the exact error when you are running your program?
In Java the error message is often very helpful to debug the issue.

a: 3
v: 2
x: 0
t: 10
The object's position is Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.Double
at java.util.Formatter$FormatSpecifier.failConversion(Unknown Source)
at java.util.Formatter$FormatSpecifier.printInteger(Unknown Source)
at java.util.Formatter$FormatSpecifier.print(Unknown Source)
at java.util.Formatter.format(Unknown Source)
at java.io.PrintStream.format(Unknown Source)
at java.io.PrintStream.printf(Unknown Source)
at GravityCalculator.main(GravityCalculator.java:36)

[Tapas Chand]

Biodun Adeniji wrote:The object's position is Exception in thread "main" java.util.IllegalFormatConversionException: d != java.lang.Double

So you can see now it is not because of the variable of type "double".
You have to have a variable of decimal type because there is a "0.5" involved.

The actual issue is with the format specifier as per the exception shows...java.util.IllegalFormatConversionException
"%d" is the format specifier for integers. It cannot be used for "double".

Now can you find the correct format specifier for "double"?

[Junilu Lacar]

On line 31, use %f instead of %d, which is for integer values, not floating point.

[Junilu Lacar]

@OP Welcome to the Ranch!

@Tapas: sorry for giving it away when you were trying to make OP work a little more. Just feeling the spirit of giving, I guess.  

[Biodun Adeniji]

Thanks @ all. The format specifier resolved the issue.

[Tapas Chand]

Junilu Lacar wrote:@Tapas: sorry for giving it away when you were trying to make OP work a little more. Just feeling the spirit of giving, I guess.  

Wishing you a merry christmas and a blessed new year...