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 meweou = 9;
int e = 2;

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

meweou / 1 % e / 5 * 2 * 4

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 noler = false;
double gao = 3.0;
double ac = 3.0;
boolean mumom = false;

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

noler != ((7 != gao) || ac > 3 || 3 >= 9) && mumom

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")

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:

• Class relationships: Correct Solution (rLyz-wusw-zrh9-j8du)
• Drawing ASTs for expressions: Correct Solution (b36t-j9sz-i5re-vku4)