What are expressions in C?

Expressions in C programming are combinations of operators, variables, constants, and functions that produce a single value. They are fundamental to performing calculations, comparisons, and other operations in a program.

Arithmetic Expressions

Arithmetic expressions consist of arithmetic operators (+, -, *, /, %) and operands (variables or constants). They are used for performing mathematical calculations.

int a = 5, b = 3; int sum = a + b; // sum is 8 int product = a * b; // product is 15

Relational Expressions

Relational expressions use comparison operators (==, !=, <, >, <=, >=) to compare two values. They result in a Boolean value (true or false).

int x = 10, y = 15; bool isEqual = (x == y); // isEqual is false bool isLess = (x < y); // isLess is true

Logical Expressions

Logical expressions combine Boolean values using logical operators ( && for AND, for OR, ! for NOT). They are used for making decisions based on multiple conditions.

bool isRaining = true, hasUmbrella = false; bool takeUmbrella = isRaining && !hasUmbrella; // takeUmbrella is true

Conditional Expressions (Ternary Operator)

The ternary operator (? :) is used to create conditional expressions with three operands. It allows you to assign different values based on a condition.

int age = 18; char* status = (age >= 18) ? "Adult" : "Minor"; // 'status' will be "Adult" because 'age' is greater than or equal to 18

Bitwise Expressions

Bitwise expressions manipulate individual bits of integer values using bitwise operators ( & for AND, for OR, ^ for XOR, ~ for NOT). They are used for low-level bit manipulation.

int num1 = 5, num2 = 3; int result = num1 & num2; // Bitwise AND (result is 1)

Function Calls

Expressions can include function calls, where a function is invoked to perform a specific task and return a value.

int square(int x) { return x * x; } int result = square(4); // Function call within an expression

Compound Expressions

Expressions can be composed of multiple sub-expressions and grouped using parentheses to control the order of evaluation.

int result = (3 + 2) * (4 - 1); // Compound expression with parentheses


Expressions are central to C programming, allowing you to perform calculations, make decisions, and control program flow by evaluating conditions. Understanding how to construct and use expressions is essential for effective C programming.