What is wrong with this program?

Question

interface shape{
int r=5;
double pi=3.14;
int h=2;
void display();
}
class sphere implements shape
{

public void display()
{
double x=(4/3)*pi*(r^3);
System.out.println("The volume of the sphere is=" +x);
}
}
class cone implements shape
{

public void display()
{
double z=(1/3)*pi*(r^2)*h;
System.out.println("The volume of the cone is="+z);
}
}

public class interf
{
public static void main(String args[])
{
sphere obj=new sphere();
obj.display();
cone obj1=new cone();
obj1.display();

}
}

Answer 1

^ is a bitwise XOR operator, which returns bit by bit OR of input values. [https://www.geeksforgeeks.org/operators-in-java/#Bitwise%20Operators] You should use Math.pow(r, 3) for sphere and Math.pow(r, 2) for cone. Remove the XOR ( ^ ) operator.

One more thing, 1/3 gives result in integer, make either the numerator or denominator a double: 1.0/3 or 1/3.0 to get a good result and not always 0. ^^