Drawing ASTs for expressions: Correct Solution

For each of the Java expressions below:

• Draw an AST for the expression.
• Show how the expression evaluates at each node in the tree.

Be sure that your tree accurately reflects how Java would evaluate the expression.

Part 1

Given the following variables:

int oop = 3;
double pa = 5.0;

...draw the AST and evaluation results for the following expression:

oop / (1 * 9 - pa)

Solution

Things to double-check in your solution:

• Do you have the left and right branches on the correct side?
• Did you indicate the difference between ints and floating point values?

Part 2

Given the following variables:

int thoci = 2;
boolean e = true;
int chewan = 9;

...draw the AST and evaluation results for the following expression:

(thoci == 0 || e) && chewan <= 5

Solution

Things to double-check in your solution:

• Does your tree correctly reflect the precedence of && and ||?
• Did you correctly show short-circuiting? (That is when the right branch of && or || is never evaluated because the left branch already determines the answer.)

Part 3

Draw the AST and evaluation results for the following expression:

0 + 1 + 2 + "3" + 4

Solution

Things to double-check in your solution:

• Did you indicate the distinction between ints and Strings?
• Are your left/right branches correct?

Related puzzles:

• Static and runtime types: Correct Solution (wtkx-hgpw-eky3-efei)
• Drawing ASTs for expressions: Correct Solution (b22L-7sk3-oge9-a4g9)