Object Oriented Programming in C++

Object Oriented Programming in C++

• C++ is a general-purpose programming language supporting various programming models, like object-oriented programming (OOP)
• Created by Bjarne Stroustrup in the early 1980s
• Commonly used for high-performance commercial software, games, and graphics
• A computer program is a set of instructions that tells a computer what to do
• Computer programs are written in high-level languages like Visual Basic, Pascal, Java, and C++
• Programs must be translated into machine language (0s and 1s) before a computer can execute them

C++ Program Structure

• Programs start with preprocessor directives, followed by the void main() function
• The void main() function is the starting point of execution
• Executable statements are placed within curly braces ({})
• The #include <iostream.h> directive is used to include input/output operations in C++ programs
• cout is used to display output on the screen
• cout<<“Information Technology”; displays "Information Technology" on the screen
• cin>>variable reads input from the user, and assigns it to the variable

Data Types

• Data types are declarations of variables for storing different types of data
• Data types in C++ include integers, floating-point numbers, double-precision numbers, and characters
• Integers represent whole numbers (e.g., -3, 0, 367, 2081)
• Floating-point numbers represent real numbers (e.g., 3.75, -2.1, 388.80)
• Characters represent single characters (e.g., 'a', '+', '%', '5')

Constants and Variables

• Constants are values that do not change during program execution (e.g., 42, 7.25, 's', "Computer")
• Variables are memory locations used to store values that may change during program execution
• Variables must be declared before use, specifying the data type (e.g., int x;, float length;)
• Variables can be initialized with a starting value (e.g., int x = 4;, float length = 12.5;)

Operators

• Operators specify actions to perform on variables or values
• Arithmetic Operators: Addition (+), subtraction (-), multiplication (*), division (/), modulo (%)
• Assignment Operators: Assign a value to a variable (e.g., =, +=, -=, *=, /=, %=)
• Relational Operators: Compare values (e.g., ==, !=, <, >, <=, >=)
• Logical Operators: Combine conditions (e.g., &&, ||, !)
• Preprocessor Directives: Control how the preprocessor handles the code before the compiler sees it (e.g., #include <headerfile.h>)

Escape Sequences

• Escape sequences are used to control output formatting and for special characters
• \n creates a new line, \t creates a tab space, \b backspace

Input/Output Operations

• cout is used to display output to the console
• cin is used to read input from the console, The keyword cin is used with the extraction operator (>>)

Manipulators

• Manipulators modify the output format
• endl inserts a new line character
• setw sets the minimum field width for output

Header Files

• Header files contain declarations of functions and variables that are used in the program
• iostream.h, conio.h, math.h, string.h, iomanip.h, time.h are some commonly used header files.