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 qaccho = 4.0;
int boncu = 4;
int re = 4;

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

6 % 1 + (qaccho % boncu / re)

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 pae = 3;
boolean hoh = false;

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

3 <= 9 && 5 != pae && hoh && 5 > 4

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

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:

• While loops and for loops: Correct Solution (2zxo-c4zb-ydxf-fu6)
• Static and runtime types: Correct Solution (wtub-oLme-svnp-dtdu)