Chapter 2: Basic Syntax and Variables

Key Points:

• Understand the different primitive data types and how to declare and initialize variables.
• Define constants using const and #define.
• Perform basic I/O operations using cin and cout.
• Utilize arithmetic, relational, logical, bitwise, and assignment operators.

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1. Data Types and Variables

A. Primitive Data Types

• int: Integer data type used to store whole numbers.
• Example: int age = 25;
• char: Character data type used to store single characters.
• Example: char grade = 'A';
• float: Floating-point data type used to store decimal numbers.
• Example: float temperature = 23.5f;
• double: Double-precision floating-point data type for larger decimal numbers.
• Example: double pi = 3.14159;
• bool: Boolean data type used to store true/false values.
• Example: bool isRaining = false;

B. Variable Declaration and Initialization

• Syntax: data_type variable_name = value;
• Example:
  cpp int number = 10; char letter = 'B'; float price = 9.99f; double distance = 384400.0; bool isAvailable = true;

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2. Constants and Literals

A. Defining Constants

• const Keyword: Used to declare constant variables whose values cannot be changed.
• Example:
  cpp const int MAX_AGE = 100;

B. #define Directive

• Macro Definition: Preprocessor directive to define constant values.
• Example:
  cpp #define PI 3.14159

C. Literals

• Integer Literals: Numeric values without decimal points.
• Example: 42
• Floating-point Literals: Numeric values with decimal points.
• Example: 3.14
• Character Literals: Single characters enclosed in single quotes.
• Example: 'A'
• String Literals: Sequence of characters enclosed in double quotes.
• Example: "Hello, World!"
• Boolean Literals: true or false.

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3. Basic I/O Operations

A. Input Using cin

• Syntax: cin >> variable;
• Example:
  cpp int age; cout << "Enter your age: "; cin >> age;

B. Output Using cout

• Syntax: cout << value;
• Example:
  cpp cout << "Hello, World!" << endl;

C. Formatting Output

• End of Line: Use endl to insert a newline.
• Example: cout << "Hello" << endl;
• Multiple Outputs: Chain multiple << operators.
• Example:
  cpp int a = 10, b = 20; cout << "a = " << a << ", b = " << b << endl;

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4. Operators

A. Arithmetic Operators

• Addition: +
• Example: int sum = 5 + 3;
• Subtraction: -
• Example: int difference = 5 - 3;
• Multiplication: *
• Example: int product = 5 * 3;
• Division: /
• Example: int quotient = 6 / 3;
• Modulus: %
• Example: int remainder = 5 % 3;

B. Relational Operators

• Equal to: ==
• Example: bool isEqual = (5 == 3);
• Not equal to: !=
• Example: bool isNotEqual = (5 != 3);
• Greater than: >
• Example: bool isGreater = (5 > 3);
• Less than: <
• Example: bool isLess = (5 < 3);
• Greater than or equal to: >=
• Example: bool isGreaterOrEqual = (5 >= 3);
• Less than or equal to: <=
• Example: bool isLessOrEqual = (5 <= 3);

C. Logical Operators

• Logical AND: &&
• Example: bool result = (5 > 3) && (5 < 10);
• Logical OR: ||
• Example: bool result = (5 > 3) || (5 < 2);
• Logical NOT: !
• Example: bool result = !(5 > 3);

D. Bitwise Operators

• AND: &
• Example: int result = 5 & 3;
• OR: |
• Example: int result = 5 | 3;
• XOR: ^
• Example: int result = 5 ^ 3;
• NOT: ~
• Example: int result = ~5;
• Left Shift: <<
• Example: int result = 5 << 1;
• Right Shift: >>
• Example: int result = 5 >> 1;

E. Assignment Operators

• Assignment: =
• Example: int a = 5;
• Add and Assign: +=
• Example: a += 3;
• Subtract and Assign: -=
• Example: a -= 3;
• Multiply and Assign: *=
• Example: a *= 3;
• Divide and Assign: /=
• Example: a /= 3;
• Modulus and Assign: %=
• Example: a %= 3;

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Practice Task:

• Write a program to take two integer inputs from the user and perform all arithmetic operations on them.
• Experiment with relational and logical operators to compare the inputs and print the results.

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