Arithmetic operators in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What are arithmetic operators in C++?

Arithmetic operators are symbols used to perform basic math operations like addition (+), subtraction (-), multiplication (*), division (/), and modulus (%).

beginner

What does the modulus operator (%) do in C++?

The modulus operator (%) gives the remainder after dividing one number by another. For example, 7 % 3 equals 1 because 7 divided by 3 leaves a remainder of 1.

intermediate

How does integer division differ from floating-point division in C++?

Integer division divides two integers and discards any decimal part, giving an integer result. Floating-point division divides numbers with decimals and keeps the fractional part.

beginner

What will be the result of this C++ expression: 5 + 3 * 2?

The result is 11 because multiplication (*) has higher priority than addition (+). So, 3 * 2 = 6, then 5 + 6 = 11.

beginner

Can arithmetic operators be used with floating-point numbers in C++?

Yes, arithmetic operators like +, -, *, and / can be used with floating-point numbers (like float or double) to perform math with decimals.

Which operator gives the remainder of a division in C++?

A %

B /

C *

D -

The % operator returns the remainder after division.

What is the result of 10 / 4 in C++ if both are integers?

A 3

B 2.5

C 2

D 4

Integer division discards the decimal part, so 10 / 4 equals 2.

Which operator has the highest precedence in this expression: 4 + 5 * 6?

A /

B +

C -

D *

Multiplication (*) has higher precedence than addition (+).

What is the output of 7 % 4 in C++?

A 4

B 3

C 1

D 7

7 divided by 4 leaves a remainder of 3.

Can you use the + operator to add two double variables in C++?

A Yes

B No

C Only if they are cast to int

D Only if they are constants

The + operator works with floating-point types like double.

Explain the difference between integer division and floating-point division in C++.

Think about dividing 7 by 2 using int and double types.

List all basic arithmetic operators in C++ and give a simple example of each.

Use numbers like 5 and 3 for examples.

Practice

1. Which arithmetic operator in C++ is used to find the remainder of a division?

easy

A. -

B. /

C. %

D. *

Solution

1. Step 1: Understand the meaning of each operator

   The operator % returns the remainder after division, while / returns the quotient.

2. Step 2: Identify the operator for remainder

   Since remainder is asked, the correct operator is %.

3. Final Answer:

   % -> Option C

4. Quick Check:

   Remainder operator = % [OK]

Hint: Remainder uses % symbol, not division / [OK]

Common Mistakes:

• Confusing / with %
• Using * for remainder
• Using - for remainder

2. Which of the following is the correct syntax to multiply two integers a and b in C++?

easy

A. a * b;

B. a x b;

C. a multiply b;

D. a . b;

Solution

1. Step 1: Recall multiplication operator syntax

   In C++, multiplication uses the asterisk symbol * between operands.

2. Step 2: Check each option

   Only a * b; uses the correct operator and syntax.

3. Final Answer:

   a * b; -> Option A

4. Quick Check:

   Multiplication operator = * [OK]

Hint: Use * for multiplication, not words or symbols [OK]

Common Mistakes:

• Using x instead of *
• Writing multiply as word
• Using dot operator for math

3. What is the output of the following C++ code?

int a = 10, b = 3;
std::cout << a / b << std::endl;

medium

A. 3.33333

B. 3

C. 4

D. Error

Solution

1. Step 1: Understand integer division in C++

   Both a and b are integers, so division truncates decimals.

2. Step 2: Calculate integer division result

   10 divided by 3 is 3.333..., but integer division returns 3.

3. Final Answer:

   3 -> Option B

4. Quick Check:

   Integer division truncates decimals = 3 [OK]

Hint: Integer division drops decimals, result is integer [OK]

Common Mistakes:

• Expecting decimal result
• Using floating-point division without casting
• Thinking output is error

4. Identify the error in this C++ code snippet:

int x = 5;
int y = 2;
int z = x / y.0;
std::cout << z << std::endl;

medium

A. Syntax error due to decimal point in divisor

B. Using floating-point literal with integer division

C. Incorrect variable declaration

D. Missing semicolon

Solution

1. Step 1: Analyze the divisor y.0

   The expression y.0 is invalid syntax in C++ because variables cannot have decimal points.

2. Step 2: Identify the syntax error

   The decimal point after y causes a syntax error; correct would be y * 1.0 or static_cast<double>(y).

3. Final Answer:

   Syntax error due to decimal point in divisor -> Option A

4. Quick Check:

   Variable names cannot have decimal points [OK]

Hint: Variable names can't have dots; causes syntax error [OK]

Common Mistakes:

• Thinking y.0 is valid float
• Ignoring syntax error
• Confusing variable and literal

5. Given int a = 7, b = 4;, which expression correctly calculates the average as a floating-point number in C++?

hard

A. a / b + 2

B. (a + b) / 2

C. a + b / 2

D. (a + b) / 2.0

Solution

1. Step 1: Understand integer vs floating-point division

   Using 2 divides integers, truncating decimals. Using 2.0 forces floating-point division.

2. Step 2: Evaluate each option

   (a + b) / 2 does integer division, result 5. (a + b) / 2.0 divides by 2.0, giving 5.5 as float. Options C and D do not calculate average correctly.

3. Final Answer:

   (a + b) / 2.0 -> Option D

4. Quick Check:

   Use floating-point divisor for decimal average [OK]

Hint: Divide by 2.0 to get decimal average, not integer [OK]

Common Mistakes:

• Using integer 2 causing truncation
• Wrong operator precedence
• Misinterpreting average formula