Random Terrain Generation in Java (Processing)

Terrain_Generation.pde

int windowX = 800; //Default 800 X 600
int windowY = 600;
int[] terrain = new int[windowX];
int count = 2;
int start;
int temp_z;

void setup(){
  background(0,0,0);
  frameRate(10000);
  size(windowX,windowY);
  noStroke();
  start = (int)random(0,windowX);
  terrain[1] = (int)random(0,windowX);
  println(terrain);
}


void draw(){
  background(0,0,0);
  fill(255,0,0);
  
  // Draws Stack
  for (int j = 0; j < terrain.length; j++){
    rect(j,terrain[j],1,windowY);
   }
    
  if (count < windowX){
    temp_z = (int)random(0,100);
    if (temp_z < random(45,55)){
      terrain[count] = terrain[count-1]+(int)random(1,2);
    } else {
      terrain[count] = terrain[count-1]-(int)random(1,2);
    }
    count++;
  }


}