Float not working with switch

Question

I have a problem with my code, I'm trying to make my script spawn a different every time I click the mouse, but I get an error with my switch because I use a random to choose a different number each time. I get this error every time I try to run the script and I can't find the error.

    Cannot switch on a value of type float. Only convertible int values, strings or enum variables are permitted

Some of the tags and names of variables is in danish as I'm danish.

int posX = 100;
int posX2 = 1820;
int dirX = 1;
int dirX2 = 1;
boolean drawforest = true;
int height = 1080;
int width = 1920;
//img = loadImage("BlueMorpho.png");
PImage img;
int storrelse = 15;
int storrelse2 = storrelse + 2;
float skift = random(0,2);

//setup()-metoden køres én gang, når sketchen startes
void drawBackground()
{
  color e = color(135, 206, 235);
  fill(e);
  rect(960, 270, 1920, 560);
}
void setup()
{
  size(1920, 1080); 
  rectMode(CENTER);
  drawBackground();
  color f = color(1, 142, 14);
  fill(f);
  rect(960, 820, 1920, 540);
  //noLoop();
}


//draw()-metoden kører i et loop, indtil den stoppes
void draw()
{
  switch(skift)
  {
  case 0:
    img = loadImage("BlueMorpho.png");
    break;
  case 1:
    img = loadImage("BlueMorpho2.png");
    break;
  default:
    img = loadImage("BlueMorpho3.png");
    break;
  }



  if (drawforest)
  {
    drawForest(); 
    drawforest = false;
  }
  drawBackground();
  drawCloud();
  drawCloud2();
  posX = posX+1;
  posX2 = posX2-1;
  if (posX>width-20 || posX<20)
  {
    dirX=-dirX;
  }
  if (posX2>width-20 || posX<20)
  {
    dirX2=-dirX2;
  }
}


void drawForest()
{
  for (int i = 0; i < 12; i++)
  {
    drawTree(random(55, 1865), 635 + 30*i);
  }
}

void drawTree(float xx, float yy)
{
  color c = color(139, 69, 19);
  fill(c);
  //noStroke();
  rect(xx, yy+30, 50, 100);
  color d = color(000, random(25, 100), 000);
  fill(d);
  //noStroke();
  ellipse(xx, yy-30, 125, 100);
  color g = color(100, 0, 0);
  fill(g);
  ellipse(random(xx-50, xx+50), random(yy-50, yy+18), 10, 10);
}

void drawCloud()
{
  color h = color(255, 255, 255);
  fill(h);
  ellipse(posX, 150, 100, 50);
  //posX += random(50,1920);
  noStroke();
}
void drawCloud2()
{
  color h = color(0, 0, 0);
  fill(h);
  ellipse(posX2, 200, 100, 50);
  //posX += random(50,1920);
}

void tegnSommerfugl(float xx, float yy)
{
  image(img, xx, yy, width/storrelse2, height/storrelse);
}

void mouseClicked()
{
  tegnSommerfugl(mouseX,mouseY);
}

You are trying to switch on the variable 'skift' which is of float type. Maybe change 'skift' to an int? — khriskooper, Aug 15 '17 at 09:08
Base problem is declaration float skift, but hard to imagine what You want at design level. Maybe should be int, but not sure — Jacek Cz, Aug 15 '17 at 09:08
Compiler is right, you cannot switch based on float, it needs to be either int, string or enum. — Pradeep Simha, Aug 15 '17 at 09:09
If `float` is needed, try to use `if`/`else if` instead of `switch`/`case`... — Usagi Miyamoto, Aug 15 '17 at 09:13
And beyond that, read about java coding style guides. Most people do not put opening braces on a new line. You **also** want to look into your naming ... having `color h` is extremely not helpful for your readers. What is "h" supposed to stand for? "huh"? "hah?" "hello"? Long story short: avoid using single character names (with the only exception of for loop index variables, and stuff like x, y). — GhostCat, Aug 15 '17 at 09:14

GhostCat · Accepted Answer · 2017-08-15T09:15:49.357

2

As the comments suggest: expected behavior. You can't switch on a variable of type float.

The answer is: that would be a bad idea anyway. Keep in mind that floating point numbers are "inaccurate" by design (see here for example). Whereas switch has the notion of exactly matching n different cases. But that is simply technically not possible for floating point numbers.

In that sense: step back, and change the type of that variable to int for example. It should be int skift - not float.

And as you then ask: "but how do I get a random int number?" - see here.

edited Aug 15 '17 at 09:15

answered Aug 15 '17 at 09:11

GhostCat

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I did use it as an int at first but then it came up and said "Cannot convert from float to int" In the reference it says that random() needs a float value, if I'm not mistaken. – Andreas2200 Aug 15 '17 at 09:13
1

See my updates. And hint: try doing some research the next time. It is not like you are entering uncharted territory where no human set foot before. – GhostCat Aug 15 '17 at 09:16

score 0 · Answer 2 · edited Jun 20 '20 at 09:12

The switch case statement works only with:

primitives: byte, short, char, int;
Classes-wrappers of the primitives: Character, Byte, Short, Integer
Enum и String (since JDK 7+)

You can use a switch on floats with up to the digits of precision you're looking for:
multiply skift for the 10..0 to shift the point as you need
then use Math.round(skift) to get the integer

or use the other random method like GhostCat said

Float not working with switch

2 Answers2