hi
 I am just starting with processing & programming

Why do I get an error when I write my mouseReleased() function after draw() and no error if I write it before? while in the simple program code#2 (with no for loop), there is no error with mouseRelease() placed after draw()

thanks!

1. int x1;
   int y1;
   
   void setup() {
     size(400, 400);
   }
   
   void mouseReleased () {
     println("x:" + mouseX + ", y:" + mouseY);
   }
   
   void draw() {
     x1 = 0; 
     y1 = 0; 
     background(255);
     for (int i = 0; i < 5; i++) {
       line(x1, y1, mouseX, mouseY);
       x1+=100;
     }
    
    //error if placed here
    
   }
   

No error with mouseRelease() placed after draw()

1. void setup () {
     size (400, 400);
   }
   
   void draw () {
     background (255);
     line (mouseX, mouseY, 0, 0);
     line (mouseX, mouseY, 100, 0);
     line (mouseX, mouseY, 200, 0);
     line (mouseX, mouseY, 300, 0);
     line (mouseX, mouseY, 400, 0);
   }
   
   void mouseReleased () {
     println("x:" + mouseX + ", y:" + mouseY);
   }