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 landu = 4.0;
int stred = 5;
int mioss = 3;
int fioccu = 1;
int pierm = 2;
double du = 5.0;
double roumbror = 5.0;
int zedtoc = 1;

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

(landu / stred / mioss / fioccu / 6 + 1 - pierm + du - roumbror) - 8 - zedtoc

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:

double e = 1.0;
int meesmred = 4;
boolean ad = false;
double ed = 3.0;
int bil = 4;
int zano = 6;
int idoi = 8;
boolean vocu = true;
int ounar = 1;
double milont = 4.0;
int nesshost = 4;

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

9 >= 8 == (!(e != meesmred)) != ad || ed <= 4 == (bil == 6) != (zano > idoi == vocu) && ounar < 4 || 7 < milont != 4 > nesshost

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" + 8 + 9 + 10 + 11

Solution

Things to double-check in your solution:

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

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