- What are operators, operands, and expressions in C
- What are arithmetic operators and how they work
- How to use addition, subtraction, multiplication, division, and modulus operators
- What is integer division and why it matters
- How to write programs using arithmetic operators
What are Operators, Operands & Expressions?
Operators are special symbols that perform specific operations on one or more operands.
Think of them like verbs in a sentence — they do the action. Examples: +, -, *, /, %.
An expression is a combination of operators and operands that produces a value.
For example, a + b is an expression where + is the operator and a, b are operands.
💡 Quick Definition: An operator is a symbol that performs an operation. An expression is a combination of operators and operands that yields a value.
C supports 8 types of operators:
- Arithmetic Operators
- Relational Operators
- Logical Operators
- Assignment Operators
- Bitwise Operators
- Increment/Decrement Operators
- Special Operators
- Conditional Operator
Types of Arithmetic Operators
C provides 5 binary arithmetic operators. These operators work on two operands:
| Operator | Symbol | Example | Description |
|---|---|---|---|
| Addition | + | a + b | Adds two numbers |
| Subtraction | - | a - b | Subtracts second number from first |
| Multiplication | * | a * b | Multiplies two numbers |
| Division | / | a / b | Divides first number by second |
| Modulus | % | a % b | Returns the remainder after division |
1. Addition Operator (+)
The addition operator is used to add two numbers or variables.
Syntax: result = operand1 + operand2;
Example: z = x + y;
2. Subtraction Operator (-)
The subtraction operator subtracts the second operand from the first.
Syntax: result = operand1 - operand2;
Example: z = x - y;
3. Multiplication Operator (*)
The multiplication operator multiplies two numbers.
Syntax: result = operand1 * operand2;
Example: z = x * y;
4. Division Operator (/)
The division operator divides the first operand by the second.
Syntax: result = operand1 / operand2;
Example: z = x / y;
⚠️ Important: In C, if both operands are integers, the result is an integer (decimal part is truncated). To get a precise result, at least one operand must be a float or double.
5. Modulus Operator (%)
The modulus operator returns the remainder when the first operand is divided by the second.
Syntax: result = operand1 % operand2;
Example: z = x % y;
The modulus operator is especially useful for:
- Checking if a number is even or odd
- Finding if a number is divisible by another
- Working with cyclic operations (like clock arithmetic)
Complete Program Example
Example: Arithmetic Operators in C
#include <stdio.h>
int main() {
int x = 9, y = 4, z;
// Addition
z = x + y;
printf("x + y = %d \n", z);
// Subtraction
z = x - y;
printf("x - y = %d \n", z);
// Multiplication
z = x * y;
printf("x * y = %d \n", z);
// Division
z = x / y;
printf("x / y = %d \n", z);
// Modulus
z = x % y;
printf("Remainder when %d divided by %d = %d \n", x, y, z);
return 0;
}
Expected Output:
x + y = 13
x - y = 5
x * y = 36
x / y = 2
Remainder when 9 divided by 4 = 1
Program Explanation
Let's break down this program line by line to understand what's happening:
1. Inclusion of Header File:
#include <stdio.h>
This includes the standard input/output library, which provides functions like printf() to display output.
2. Variable Declaration:
int x = 9, y = 4, z;
x is initialized with 9, y with 4, and z is left uninitialized to store results.
3. Addition Operation:
z = x + y;
printf("x + y = %d \n", z);
Adds 9 and 4 to get 13, stores in z, and prints the result.
4. Subtraction Operation:
z = x - y;
printf("x - y = %d \n", z);
Subtracts 4 from 9 to get 5, stores in z, and prints the result.
5. Multiplication Operation:
z = x * y;
printf("x * y = %d \n", z);
Multiplies 9 and 4 to get 36, stores in z, and prints the result.
6. Division Operation (Integer Division):
z = x / y;
printf("x / y = %d \n", z);
Divides 9 by 4. Since both are integers, the result is an integer — 2, not 2.25. The decimal part is truncated.
7. Modulus Operation:
z = x % y;
printf("Remainder when %d divided by %d = %d \n", x, y, z);
Returns the remainder when 9 is divided by 4, which is 1.
8. Return Statement:
return 0;
Indicates that the program executed successfully and returns control to the operating system.
Summary of Arithmetic Operators
| Operator | Symbol | Function | Example |
|---|---|---|---|
| Addition | + | Add two numbers | 5 + 3 = 8 |
| Subtraction | - | Subtract Second from First | 5 - 3 = 2 |
| Multiplication | * | Multiply two numbers | 5 * 3 = 15 |
| Division | / | Divide & return quotient | 5 / 3 = 1 |
| Modulus | % | Returns the remainder | 5 % 3 = 2 |
🎯 Key Takeaway: Arithmetic operators are the building blocks of mathematical operations in C. They are used in billing systems, games, reports, financial applications, IoT sensors — everywhere calculations are needed.
Frequently Asked Questions About Arithmetic Operators
1. What is the difference between / and % in C?
/ is the division operator that returns the quotient. % is the modulus operator that returns the remainder after division.
2. Why does 9/4 give 2 instead of 2.25 in C?
This is called integer division. When both operands are integers, C performs integer division and truncates the decimal part.
3. How can I get the exact decimal result in division?
Make at least one operand a float or double. For example: 9.0 / 4 or (float)9 / 4.
4. Where are arithmetic operators used in real life?
Arithmetic operators are used everywhere — billing systems, game development, financial applications, scientific calculations, IoT sensors, and more.
💡 Tip: Practice writing programs with all five arithmetic operators to build a strong foundation in C programming.