Operator precedence in Java - Step-by-Step Execution

Concept Flow - Operator precedence

Start Expression

↓

Identify Operators

↓

Check Precedence Levels

↓

Evaluate Highest Precedence Operator

↓

Replace with Result

↓

Repeat Until Expression Fully Evaluated

↓

Final Result

The expression is evaluated by first identifying operators, then applying them in order of their precedence from highest to lowest until the entire expression is evaluated.

Execution Sample

Java

int result = 3 + 4 * 2;
System.out.println(result);

Calculates 3 plus 4 times 2, showing how multiplication happens before addition.

Execution Table

Step	Expression	Operator Evaluated	Operation	Resulting Expression
1	3 + 4 * 2	*	4 * 2 = 8	3 + 8
2	3 + 8	+	3 + 8 = 11	11
3	11	None	Expression fully evaluated	11

💡 No more operators left, final result is 11

Variable Tracker

Variable	Start	After Step 1	After Step 2	Final
result	undefined	undefined	undefined	11

Key Moments - 2 Insights

Why does multiplication happen before addition in the expression?

Because multiplication has higher precedence than addition, as shown in step 1 of the execution_table where 4 * 2 is evaluated before adding 3.

What if we want addition to happen first?

We can use parentheses to change precedence, for example (3 + 4) * 2, which would evaluate addition first.

Visual Quiz - 3 Questions

Look at the execution_table, what is the expression after step 1?

A 3 + 8

B 7 * 2

C 3 + 4

D 11

💡 Hint

Check the 'Resulting Expression' column in row for step 1.

At which step is the addition operator evaluated?

A Step 1

B Step 2

C Step 3

D Never

💡 Hint

Look at the 'Operator Evaluated' column to find when '+' is processed.

If the expression was (3 + 4) * 2, what would be the first operation evaluated?

A 3 * 2

B 4 * 2

C 3 + 4

D Addition and multiplication at the same time

💡 Hint

Parentheses change precedence, so check what is inside them first.

Concept Snapshot

Operator precedence determines the order in which parts of an expression are calculated.
Higher precedence operators (like *) are evaluated before lower ones (like +).
Use parentheses () to change the order explicitly.
Example: 3 + 4 * 2 equals 3 + (4 * 2) = 11.
Without parentheses, multiplication and division happen before addition and subtraction.

Full Transcript

Operator precedence in Java means some operations happen before others in an expression. For example, multiplication (*) has higher precedence than addition (+). In the code 'int result = 3 + 4 * 2;', the multiplication 4 * 2 is done first, resulting in 8, then 3 + 8 equals 11. This is shown step-by-step in the execution table. If you want addition first, use parentheses like (3 + 4) * 2. This changes the order and the result. Understanding operator precedence helps avoid mistakes and write correct expressions.