Game Development Reference
In-Depth Information
12. Variable assignment
Consider the following two variable declarations and assignments:
int x, y;
x = 40;
y = 12;
Indicate for each of the following groups of instructions what the values of x
and y are when these instructions are executed after the above declarations and
instructions.
y=x+1;
x=y+1;
x=y;
y=x;
x=y+1;
y=x
x = x+y;
y=x
y=x/3;
x=y
y=2/3
x;
y=x%6;
x=x/6;
1;
y;
3;
x=2
x/3;
x=x
y;
In one of the cases, the values of x and y are swapped. Does this work for all
possible values of x and y ? If so, why is that? If not, in what cases does it
fail?
13. Multiplying and dividing
Is there a difference between the following three instructions?
3 time / 2;
position = 300
3/2 time;
position = 300
time/2 3;
position = 300
14. Hours, minutes, seconds
Suppose that the integer variable time contains a (possibly large) number of
seconds. Write down a number of instructions that assign a value to the vari-
ables hours , minutes and seconds corresponding to their meaning, where the
values of minutes and seconds should be smaller than 60. Secondly, write the
instruction that performs the reverse operation. So, given the variables hours ,
minutes , and seconds , calculate the value that the variable time should con-
tain.
15. The game loop
Which actions does the game loop consist of? Which actions are executed only
once, and which actions are executed multiple times? What is the use of these
different actions?
16. Updating and drawing
We could put all the code from the Update method in the Draw method, and
leave out the Update method altogether. Why is it still useful to have different
methods?
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