Java Basics 104 – Operator Precedence

STEPS

1) Browse http://ideone.com/1gau2Z

http://ideone.com/1gau2Z

2) Three numbers operation

Change line no. 13 to:

int first_number, second_number, third_number, answer;

Change line no.14-15 to:

first_number = 100;

second_number = 75;

third_number = 25;

Change line no. 16 to:

answer = first_number - second_number + third_number;

Change line no.18 to:

System.out.println("Total = " + answer );

Outcome:

http://ideone.com/Uwh99a

3) Three numbers operation with bracket 1

Change line no. 17 to:

answer = (first_number - second_number) + third_number;

Outcome:

http://ideone.com/pvedQe

4) Three numbers operation with bracket 2

Change line no. 17 to:

answer = first_number - (second_number + third_number);

Outcome:

http://ideone.com/qxudcb

5) Three numbers operation with + and *

Change line no. 17 to:

answer = first_number + second_number * third_number;

Outcome:

http://ideone.com/UZPD18

The following codes also leads to the same outcome:

answer = first_number + (second_number * third_number);

Outcome: http://ideone.com/3AQzNT

Change the position of the brackets as follows. What would be the outcome?

answer = (first_number + second_number) * third_number;

Outcome: http://ideone.com/j0jI5j

6) Three numbers operation with () and /

Change line no. 17 as follows. What is the outcome?

answer = first_number + second_number / third_number;

Outcome: http://ideone.com/qzwpyM

Change line no. 17 as follows. What is the outcome?

answer = (first_number + second_number) / third_number;

Outcome: http://ideone.com/IiGGKn

LESSONS:

Here's a list on Operator Precedence

Multiply and Divide - Treated equally, but have priority over Addition and Subtraction
Add and Subtract - Treated equally but have a lower priority than multiplication and division

So if you think Java is giving you the wrong answer, remember that Operator Precedence is important, and add some round brackets.

REFERENCE

http://www.homeandlearn.co.uk/java/operator_precedence.html