11 - PDPS.md

Question 1. Consider the code given below and answer the following questions:

boolean meFailEnglish = true;
int warnerBrothers = 4;
int tom = 0, jerry = 0;

void setup() {
  size(400, 400); background(0);
}

void draw() 
{
  rect(tom, jerry, width/warnerBrothers, height/warnerBrothers);
  tom+=2*width/warnerBrothers;
  if (tom >= width) {
    if (meFailEnglish)
    {
      tom = width/warnerBrothers;
    } 
    else
      tom = 0;
    meFailEnglish = !!!meFailEnglish;
    jerry+=height/warnerBrothers;
  }
}

1. What aspects (in terms of coding style) of the program can be improved?
2. What changes should I introduce if I want the top-left cell to be black (instead of white)? That is, I would like to rotate the grid by 90 degrees (clock-wise or anti-clockwise). Don't use rotate()/pushMatrix()/popMatrix. Do it by simple manipulation of the existing program.
3. What aspect of the program makes it scalable?
4. (HD) There is a very subtle bug in the program. Identify and fix it.

Question 2

Explain what magic numbers are and how we may refactor our code to remove them. Furthermore, what advantages does removing magic numbers have?

Question 3

Refactor the following code to use a loop.

println("#");
println("##");
println("###");
println("####");

Why is using a loop better than manually printing each row of the pyramid?

Question 4

Why is top-down design called a divide and conquer strategy?