I want to calculate the distance between two points in Java

Question

OK  so I ve written most of a program that will allow me to determine if two circles overlap    I have no problems whatsoever with my program aside from one issue  the program won t accept the code I ve written for the distance between the two center points  I can figure out the if else logic to tell the user what happens depending on the value of distance later  but I want to know what s wrong now  Eclipse  the program I m coding on  is telling me that distance should be resolved to an array  but I ve already told you that it s an int    Here is my code   package circles  import java util Scanner   public class MathCircles              variable for the distance between the circles  centers     public static int distance          variable for the lengths of the radii combined     public static int radii       public static void main String   args               Get the x-value of the center of circle one         System out println  What is the x-coordinate for the center of circle one             Scanner keyboard   new Scanner System in           int x1   keyboard nextInt               Get the y-value of the center of circle one         System out println  What is the y-coordinate for the center of circle one             Scanner keyboard1   new Scanner System in           int y1   keyboard1 nextInt               Get the radius length of circle one          System out println  How long is circle one s radius             Scanner keyboard2   new Scanner System in           int r1   keyboard2 nextInt                Get the x-value of the center of circle two          System out println  What is the x-coordinate for the center of circle two             Scanner keyboard3   new Scanner System in           int x2   keyboard3 nextInt               Get the y-value of the center of circle two          System out println  What is the y-coordinate for the center of circle two             Scanner keyboard4   new Scanner System in           int y2   keyboard4 nextInt               Get the radius length of circle two          System out println  How long is circle two s radius             Scanner keyboard5   new Scanner System in           int r2   keyboard5 nextInt                           OK  so now I have the location of the two circles  centers             as well as the lengths of their radii             The circles are intersecting IF THE DISTANCE BETWEEN THE TWO CENTERS            IS EQUAL TO OR LESS THAN THE COMBINED LENGTHS OF THE RADII             Now I need to get some math done                         calculate the combined lengths of the radii          radii   r1   r2             calculate the distance         distance   Math sqrt  x1-x2  x1-x2     y1-y2  y1-y2

User · Answer

Unlike maths-on-paper notation  most programming languages  Java included  need a   sign to do multiplication  Your distance calculation should therefore read   distance   Math sqrt  x1-x2   x1-x2     y1-y2   y1-y2      Or alternatively   distance   Math sqrt Math pow  x1-x2   2    Math pow  y1-y2   2

User · Answer

Based on the  trashgod s comment  this is the simpliest way to calculate distance   double distance   Math hypot x1-x2  y1-y2     From documentation of Math hypot      Returns  sqrt x    y     without intermediate overflow or underflow

User · Answer

Math sqrt returns a double so you ll have to cast it to int as well  distance    int Math sqrt  x1-x2   x1-x2     y1-y2   y1-y2

User · Answer

You could also you Point2D Java API class   public static double distance double x1  double y1  double x2  double y2   Example   double distance   Point2D distance 3 0  4 0  5 0  6 0   System out println  The distance between the points is     distance

User · Answer

You need to explicitly tell Java that you wish to multiply    x1-x2     x1-x2     y1-y2     y1-y2    Unlike written equations the compiler does not know this is what you wish to do

User · Answer

This may be OLD  but here is the best answer       float dist    float  Math sqrt              Math pow x1 - x2  2                Math pow y1 - y2  2

User · Answer

Based on the  trashgod s comment  this is the simpliest way to calculate  gt distance  double distance   Math hypot x1-x2  y1-y2   From documentation of Math hypot  Returns  sqrt x    y    without intermediate overflow or underflow  Bob  Below Bob s approved comment he said he couldn t explain what the Math hypot x1-x2  y1-y2    did  To explain a triangle has three sides  With two points you can find the length of those points based on the x y of each  Xa 0  Ya 0 If thinking in Cartesian coordinates that is  0 0  and then Xb 5  Yb 9 Again  cartesian coordinates is  5 9   So if you were to plot those on a grid  the distance from from x to another x assuming they are on the same y axis is  5  and the distance along the Y axis from one to another assuming they are on the same x-axis is  9   think number line  Thus one side of the triangle s length is 5  another side is 9  A hypotenuse is   x 2     y 2    Hypotenuse 2  which is the length of the remaining side of a triangle  Thus being quite the same as a standard distance formula where  Sqrt of  x1-x2  2    y1-y2  2   distance   because if you do away with the sqrt on the lefthand side of the operation and instead make distance 2 then you still have to get the sqrt from the distance  So the distance formula is the Pythagorean theorem but in a way that teachers can call it something different to confuse people

[java] I want to calculate the distance between two points in Java

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