Operator precedence in MATLAB - Practice Problems & Coding Challenges

Challenge - 5 Problems

❓ Predict Output

intermediate

What is the output of this MATLAB code?

Consider the following MATLAB code snippet. What value does variable result hold after execution?

MATLAB

result = 3 + 4 * 2;

A 11

B 14

C 10

D 7

💡 Hint

Remember that multiplication (*) has higher precedence than addition (+).

In MATLAB, multiplication (*) is done before addition (+). So, 4 * 2 = 8, then 3 + 8 = 11.

❓ Predict Output

intermediate

What is the output of this MATLAB expression with parentheses?

What value does result hold after running this code?

MATLAB

result = (3 + 4) * 2;

A 7

B 11

C 10

D 14

💡 Hint

Parentheses change the order of operations.

Parentheses force MATLAB to add 3 + 4 first, which is 7, then multiply by 2, resulting in 14.

❓ Predict Output

advanced

What is the output of this MATLAB logical expression?

What is the value of result after running this code?

MATLAB

result = 5 > 3 & 2 < 1 | 4 == 4;

A 1

B 0

C [1 0]

D Error

💡 Hint

Logical AND (&) has higher precedence than OR (|).

First, 5 > 3 is true (1), 2 < 1 is false (0), so 1 & 0 = 0. Then 4 == 4 is true (1). Finally, 0 | 1 = 1.

❓ Predict Output

advanced

What is the output of this MATLAB expression with power and negation?

What value does result hold after running this code?

MATLAB

result = -2^2;

A -2

B 4

C -4

D Error

💡 Hint

Exponentiation (^) has higher precedence than unary minus (-).

MATLAB calculates 2^2 first, which is 4, then applies the unary minus, resulting in -4.

❓ Predict Output

expert

What is the output of this complex MATLAB expression?

What value does result hold after running this code?

MATLAB

result = 10 / 2 * 3 ^ 2 - 4 + 1;

A 47

B 42

C 45

D 39

💡 Hint

Remember the order: power (^), then multiplication/division (*,/), then addition/subtraction (+,-).

Operator precedence in MATLAB: ^ > * / > + -
Same precedence operators are evaluated left to right.

Step-by-step:
1. 3 ^ 2 = 9
2. 10 / 2 * 9 = (10 / 2) * 9 = 5 * 9 = 45
3. 45 - 4 + 1 = (45 - 4) + 1 = 41 + 1 = 42

Practice

1. In MATLAB, which operator has the highest precedence in the expression 3 + 4 * 2?

easy

A. Subtraction (-)

B. Addition (+)

C. Division (/)

D. Multiplication (*)

Solution

1. Step 1: Recall operator precedence rules

   Multiplication and division have higher precedence than addition and subtraction in MATLAB.

2. Step 2: Apply precedence to the expression

   In 3 + 4 * 2, multiplication happens first, so 4 * 2 = 8, then addition: 3 + 8 = 11.

3. Final Answer:

   Multiplication (*) -> Option D

4. Quick Check:

   Multiplication before addition = Multiplication (*) [OK]

Hint: Multiply/divide before add/subtract unless parentheses used [OK]

Common Mistakes:

• Adding before multiplying
• Ignoring operator precedence
• Assuming left-to-right always applies

2. Which of the following MATLAB expressions correctly uses parentheses to ensure addition happens before multiplication?

easy

A. 3 + (4 * 2)

B. 3 + 4 * 2

C. (3 + 4) * 2

D. 3 * 4 + 2

Solution

1. Step 1: Understand parentheses effect

   Parentheses force MATLAB to calculate inside them first, overriding normal precedence.

2. Step 2: Check each expression

   Only (3 + 4) * 2 adds 3 and 4 first, then multiplies by 2.

3. Final Answer:

   (3 + 4) * 2 -> Option C

4. Quick Check:

   Parentheses change order = (3 + 4) * 2 [OK]

Hint: Use parentheses to change normal operator order [OK]

Common Mistakes:

• Ignoring parentheses effect
• Assuming multiplication always first
• Misplacing parentheses

3. What is the output of the following MATLAB code?

a = 5 + 3 * 2 / 6 - 1;

medium

A. 5.0

B. 6

C. 6.0

D. 5

Solution

1. Step 1: Calculate multiplication and division first

   Calculate 3 * 2 = 6, then 6 / 6 = 1.

2. Step 2: Perform addition and subtraction left to right

   Expression becomes 5 + 1 - 1, which is 5.0.

3. Final Answer:

   5.0 -> Option A

4. Quick Check:

   Multiply/divide first, then add/subtract = 5.0 [OK]

Hint: Multiply/divide before add/subtract, left to right [OK]

Common Mistakes:

• Adding before multiplying
• Ignoring division precedence
• Confusing integer and floating-point output

4. Identify the error in this MATLAB expression:

result = 4 + * 3;

medium

A. No error, valid expression

B. Syntax error due to misplaced operator

C. Runtime error due to undefined variable

D. Logical error in calculation

Solution

1. Step 1: Analyze the expression syntax

   The expression 4 + * 3 has two operators '+' and '*' without a number between them, which is invalid syntax.

2. Step 2: Confirm MATLAB error type

   MATLAB will throw a syntax error because the operator '*' cannot directly follow '+'.

3. Final Answer:

   Syntax error due to misplaced operator -> Option B

4. Quick Check:

   Operators must have operands between them [OK]

Hint: Check operators have numbers on both sides [OK]

Common Mistakes:

• Assuming expression is valid
• Ignoring operator placement rules
• Confusing syntax and runtime errors

5. Given the MATLAB expression:

value = 10 - 2 * (3 + 1) / 2 + 4;

What is the correct value of value after MATLAB evaluates it?

hard

A. 10

B. 8

C. 6

D. 12

Solution

1. Step 1: Calculate inside parentheses first

   (3 + 1) = 4.

2. Step 2: Perform multiplication and division next

   Calculate 2 * 4 = 8, then 8 / 2 = 4.

3. Step 3: Perform addition and subtraction left to right

   Expression becomes 10 - 4 + 4. Since + and - have same precedence and are left-associative: 10 - 4 = 6, then 6 + 4 = 10.

4. Final Answer:

   10 -> Option A

5. Quick Check:

   Parentheses, then multiply/divide, then add/subtract = 10 [OK]

Hint: Calculate parentheses first, then multiply/divide, then add/subtract [OK]

Common Mistakes:

• Adding before subtracting
• Ignoring parentheses
• Doing operations out of order