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 riashi = 3;
int prenxher = 1;
int denoc = 5;
int prel = 6;
int nepkosm = 4;

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

2 - riashi + prenxher + denoc + prel - nepkosm + 7

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 tifos = false;
double hism = 2.0;
int rhusia = 3;
boolean miomu = true;
int a = 4;

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

(tifos || !(hism > 1) != 7 < rhusia && 5 == 7 && miomu) && 5 <= a

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:

• Static and runtime types: Correct Solution (wtch-gn7k-sufk-7eoz)
• Drawing ASTs for expressions: Correct Solution (b1qi-q176-2sat-f40h)