Processing test #1 - Answers

// Processing test 1

void setup() {
  size(600,400);
  background(200);  // light gray
  
  // test Problem #1: MyPower():
  //println(MyPower(2,3),MyPower(2,-3));
  
  // test Probem #2: int2String()
  // println(Int2String(23),Int2String(987004),Int2String(23034));
  // println(Int2String2(23),Int2String2(987004),Int2String2(23034));
  
  // test Problem #3
  // VerticalCircles();
  
  // test Extra credit
  // CrossHatch();
}
// =======================   Problem #1
float MyPower(float base, int exponent) {
  int i;
  float answer = 1.0;
  if (exponent == 0)
    return answer;
    
  if (exponent > 0) {
    for (i = 1; i <= exponent; ++i)
      answer *= base;
  } 
  
  else {
    for (i = -1; i >= exponent; --i)
      answer /= base;
  }
  
  return answer;
}

// ========================  Problem #2 Version 1
String Int2String(int n) {
  String sn = str(n);
  if (n < 1000)
    return sn;
  return sn.substring(0,sn.length()-3) + "," + sn.substring(sn.length()-3);
}

// ========================  Problem #2  Version 2
String Int2String2(int n) {
  int thousands, ones;
  
  if (n < 1000)  // no comma necessary
    return str(n);
    
  thousands = n / 1000;  // remember: this is integer division
  ones = n % 1000;
  if (ones >= 100)
    return str(thousands) + "," + str(ones);
    
  if (ones >= 10)
    return str(thousands) + ",0" + str(ones);
    
  return str(thousands) + ",00" + str(ones);
}

// ==================================== Problem #3
void VerticalCircles() {
  int i;
  
  line(0,0,600,400);  // this line is behind the circles, so must be drawn first
  
  // there are 9 circles with diameter 50
  for (i = 0; i < 9; i++) {
    fill(i*255/8);  // when i == 0, this is black, when i == 8, this is white
    circle(300,i*50,50);
  }
  
  line(600,0,0,400); // this line is on top of the circles
}

// ================================= Extra credit
void CrossHatch() {
  background(230);  // close to white
  
  for (int i = 0; i <= 600; i += 50)
    DrawFromABottomPoint(i);
}

void DrawFromABottomPoint(int bottom) {
  for (int i = 0; i <= 600; i += 50) 
    line(bottom, 400, i, 0);
}