Spring 2001  CS100M  Exercise E2: Basic tracing     due in Lecture, 2/1

Try to trace things by hand, on paper, away from the computer.

If you get stuck, try running part of the code: just enough to get
unstuck.

At the end, you can get check your answers by running all the code in
Matlab.

Turn in your hand-traced answers for all three questions.

1. Use the tabular format to trace the following code:


    z = 1; 
    for x = [3 1 4 6]
	w = z;
	for y = [2 7]
	    z = z + w * y;
	    if rem(z, 3) == 0
	        z = (z+0)/3;
	    end
	end
    end

2. Use the box diagram memory model to trace the following code:

    genny.age = 13;
    genny.friends = 7;
    rosie = struct('age', genny.age-2, 'toys',8);
    junie = genny;
    genny.age = 14;
    y = junie.age;
    genny = rosie;
    junie.sister = rosie;

3. Use the box diagram memory model to trace the code:

    x = [ 5 1 4 8 2 6 3 9 7 ];
    i = 3;
    for j = 1:5
	i = x(i)+1;
	if i <= length(x)
	    x(i) = x(i)+1;
	else
	    x = [x j];
	end
    end