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:

double sont = 3.0;
int khucer = 7;
int kanir = 3;
int zossass = 6;

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

(0 % sont) - khucer + kanir + 0 + zossass * 6

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:

boolean cicrhi = true;
boolean padvo = false;
int ar = 2;

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

4 >= 6 == (0 > 1 == 0 > 3 && !cicrhi) || padvo == 6 >= ar

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") + 5 + "6" + 7

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:

• Drawing ASTs for expressions: Correct Solution (b5qg-dn37-mjyd-5g5y)
• Class relationships: Correct Solution (rLih-cdsc-Lcxo-jak5)