I was doing some coding then all of a sudden without changing anything (that i am aware of) it just stopped working.

Can you guys please tell me what you see is wrong with it?

Main code:

int maxBalls = 20;
Ball[] ballArray;
int ballCount; // No of balls being created

//Background colour variables
float a = 0;
float b = 0;
float c = 0;
float d = 102;
float e = 204;
float f = 255;

//controls
int edge = 56;
int radius = 0;
int radicont = 1;

void setup() {
  size(750, 750);
  smooth();
  // Create an array of balls
  ballArray = new Ball[maxBalls];
}

void background1()
{
  background(color(d+a,e+b,f+c));
  //Change the background colours
  a = (random(-1,1)) + a;
  b = (random(-1,1)) + b;
  c = (random(-1,1)) + c;
  //black border
  fill(0);
  rect(0,0,edge,height);
  rect(0,0,width,edge);
  rect(0,height-edge,width,height);
  rect(width-edge,0,width,height);
  noFill();
}

void draw() {
  background1();
  // Display the balls and update the positions
  for (int i = 0; i < ballCount-1; i++) {
    ballArray[i].display();
    ballArray[i].update();
    ballArray[i].mouse();
  }
}

void mousePressed() {
  if (mouseButton == LEFT) {
    if (ballCount < maxBalls) {
      ballArray[ballCount] = new Ball(mouseX, mouseY, random(-2, 2), random(-2, 2), 10.0);
      ballCount++;
      if(ballCount == maxBalls)  {
        ballCount = maxBalls - ballCount;
    }
  }
}


Ball class code:

class Ball {
  float x, y; // Position of the ball
  float speedX, speedY; // Speed of the ball
  float radius; // Radius of the ball
  color ball_color = color(0,random(0,250)); // Color of the ball
  int resizeControl = 0;

  // Constructor
  Ball(float x_, float y_, float speedX_, float speedY_, float radius_) {
    x = x_;
    y = y_ ;
    speedX = speedX_;
    speedY = speedY_;
    radius = radius_;
  }

  // Draws the ball
  void display() {
    fill(ball_color);
    stroke(ball_color);
    ellipse(x, y, radius * 2, radius * 2);
  }

  // Updates the ball's position, and reverses speed if it hits the wall
  void update() {
    x = x + speedX* mouseY/100;
    y = y + speedY* mouseY/100;
    // Reverse speed if it hits the wall
    if (x + edge + radius > width || x - edge - radius < 0) {
      speedX = - speedX;
    }
    if (y + edge + radius > height || y -  edge - radius < 0) {
      speedY = - speedY;
    }
  }

  void mouse() {
    if (mousePressed) {
      resizeControl = 1;
      if(mouseButton == RIGHT) {

        if (resizeControl == 1) {
          if(radius<50 && radicont==1) {

            radius=radius+1;
            if(radius==49) {
              radicont=0;
            }
          }
          if(radius>10 && radicont==0) {

            radius=radius-1;
            if(radius==11) {
              radicont=1;
            }
          }
        }
      }
      else if (mouseButton == LEFT) {   
        resizeControl = 0;
      }
    }
  }
}


I am aware of the error and what it means but whatever i change it just wont work.

thanks for the help.