Expressions in C++

 Expressions in C++

An expression in C++ is a combination of:

• Operands → variables, constants, literals
• Operators → +, -, *, /, ==, &&, etc.

An expression produces a value.

 

Example:

a + b      // arithmetic expression

x > 10     // relational expression

i++        // increment expression

flag && x  // logical expression

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Types of Expressions in C++

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1 Arithmetic Expressions

Used for numeric calculations.

Operators:

+ - * / %

 

Example:

int a = 10, b = 3;

int c = a + b * 2;   // result = 16

 

Key Point:

Operator precedence affects the result
* , / , % have higher precedence than + , -.

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2 Relational Expressions

Used to compare two values (returns true/false).

Operators:

== != > < >= <=

Example:

int x = 10;

bool result = (x >= 10);   // true

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3 Logical Expressions

Used for decision-making.

Operators:

&& || !

 

Example:

int age = 20;

bool ok = (age >= 18 && age <= 40); // true

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4 Assignment Expressions

Stores a value in a variable.

Operators:

= += -= *= /= %=

Example:

int x = 5;

x += 3;    // x = x + 3 = 8

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5 Increment & Decrement Expressions

++ → increase by 1
-- → decrease by 1

Two Types:

• Pre-increment: ++x
• Post-increment: x++

Expression	Meaning	Example
++x	increments first, then uses value	y = ++x;
x++	uses value first, then increments	y = x++;

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6 Conditional Expression (Ternary Operator)

Short form of if-else.

Syntax:

condition? expression1 : expression2

Example:

int marks = 70;

string result = (marks >= 40) ? "Pass" : "Fail";

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7 Bitwise Expressions

Works at bit level.

& | ^ ~ << >>

 

Example:

int x = 5 & 3;   // 0101 & 0011 = 0001 = 1

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8 Pointer Expressions

Used with memory addresses.

Example:

int a = 10;

int *ptr = &a;

 

cout << *ptr;  // value at address

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Operator Precedence

From highest to lowest:

1. ()
2. ++, -- (prefix)
3. *, /, %
4. +, -
5. <, <=, >, >=
6. ==, !=
7. &&
8. ||
9. =, +=, -= ...