C++ Tutorial
C++ is a popular programming language.
C++ is used to create computer programs.
Example
#include <iostream>
using namespace std;
int main() {
cout << "Hello World!";
return 0;
}C++ is a middle-level programming language developed by Bjarne Stroustrup starting in 1979 at Bell Labs. C++ runs on a variety of platforms, such as Windows, Mac OS, and the various versions of UNIX. This C++ tutorial adopts a simple and practical approach to describe the concepts of C++ for beginners to advanded software engineers.
Why to Learn C++
C++ is a MUST for students and working professionals to become a great Software Engineer. I will list down some of the key advantages of learning C++:
C++ is very close to hardware, so you get a chance to work at a low level which gives you lot of control in terms of memory management, better performance and finally a robust software development.
C++ programming gives you a clear understanding about Object Oriented Programming. You will understand low level implementation of polymorphism when you will implement virtual tables and virtual table pointers, or dynamic type identification.
C++ is one of the every green programming languages and loved by millions of software developers. If you are a great C++ programmer then you will never sit without work and more importantly you will get highly paid for your work.
C++ is the most widely used programming languages in application and system programming. So you can choose your area of interest of software development.
C++ really teaches you the difference between compiler, linker and loader, different data types, storage classes, variable types their scopes etc.
There are 1000s of good reasons to learn C++ Programming. But one thing for sure, to learn any programming language, not only C++, you just need to code, and code and finally code until you become expert.
Applications of C++ Programming
As mentioned before, C++ is one of the most widely used programming languages. It has it's presence in almost every area of software development. I'm going to list few of them here:
Application Software Development - C++ programming has been used in developing almost all the major Operating Systems like Windows, Mac OSX and Linux. Apart from the operating systems, the core part of many browsers like Mozilla Firefox and Chrome have been written using C++. C++ also has been used in developing the most popular database system called MySQL.
Programming Languages Development - C++ has been used extensively in developing new programming languages like C#, Java, JavaScript, Perl, UNIX’s C Shell, PHP and Python, and Verilog etc.
Computation Programming - C++ is the best friends of scientists because of fast speed and computational efficiencies.
Games Development - C++ is extremely fast which allows programmers to do procedural programming for CPU intensive functions and provides greater control over hardware, because of which it has been widely used in development of gaming engines.
Embedded System - C++ is being heavily used in developing Medical and Engineering Applications like softwares for MRI machines, high-end CAD/CAM systems etc.
This list goes on, there are various areas where software developers are happily using C++ to provide great softwares. I highly recommend you to learn C++ and contribute great softwares to the community.
Audience
This C++ tutorial has been prepared for the beginners to help them understand the basic to advanced concepts related to C++.
Prerequisites
Before you start practicing with various types of examples given in this C++ tutorial,we are making an assumption that you are already aware of the basics of computer program and computer programming language.
C++ is a statically typed, compiled, general-purpose, case-sensitive, free-form programming language that supports procedural, object-oriented, and generic programming.
C++ is regarded as a middle-level language, as it comprises a combination of both high-level and low-level language features.
C++ was developed by Bjarne Stroustrup starting in 1979 at Bell Labs in Murray Hill, New Jersey, as an enhancement to the C language and originally named C with Classes but later it was renamed C++ in 1983.
C++ is a superset of C, and that virtually any legal C program is a legal C++ program.
Note − A programming language is said to use static typing when type checking is performed during compile-time as opposed to run-time.
Object-Oriented Programming
C++ fully supports object-oriented programming, including the four pillars of object-oriented development −
- Encapsulation
- Data hiding
- Inheritance
- Polymorphism
Standard Libraries
Standard C++ consists of three important parts −
The core language giving all the building blocks including variables, data types and literals, etc.
The C++ Standard Library giving a rich set of functions manipulating files, strings, etc.
The Standard Template Library (STL) giving a rich set of methods manipulating data structures, etc.
The ANSI Standard
The ANSI standard is an attempt to ensure that C++ is portable; that code you write for Microsoft's compiler will compile without errors, using a compiler on a Mac, UNIX, a Windows box, or an Alpha.
The ANSI standard has been stable for a while, and all the major C++ compiler manufacturers support the ANSI standard.
Learning C++
The most important thing while learning C++ is to focus on concepts.
The purpose of learning a programming language is to become a better programmer; that is, to become more effective at designing and implementing new systems and at maintaining old ones.
C++ supports a variety of programming styles. You can write in the style of Fortran, C, Smalltalk, etc., in any language. Each style can achieve its aims effectively while maintaining runtime and space efficiency.
Use of C++
C++ is used by hundreds of thousands of programmers in essentially every application domain.
C++ is being highly used to write device drivers and other software that rely on direct manipulation of hardware under realtime constraints.
C++ is widely used for teaching and research because it is clean enough for successful teaching of basic concepts.
Anyone who has used either an Apple Macintosh or a PC running Windows has indirectly used C++ because the primary user interfaces of these systems are written in C++.
Local Environment Setup
If you are still willing to set up your environment for C++, you need to have the following two softwares on your computer.
Text Editor
This will be used to type your program. Examples of few editors include Windows Notepad, OS Edit command, Brief, Epsilon, EMACS, and vim or vi.
Name and version of text editor can vary on different operating systems. For example, Notepad will be used on Windows and vim or vi can be used on windows as well as Linux, or UNIX.
The files you create with your editor are called source files and for C++ they typically are named with the extension .cpp, .cp, or .c.
A text editor should be in place to start your C++ programming.
C++ Compiler
This is an actual C++ compiler, which will be used to compile your source code into final executable program.
Most C++ compilers don't care what extension you give to your source code, but if you don't specify otherwise, many will use .cpp by default.
Most frequently used and free available compiler is GNU C/C++ compiler, otherwise you can have compilers either from HP or Solaris if you have the respective Operating Systems.
Installing GNU C/C++ Compiler
UNIX/Linux Installation
If you are using Linux or UNIX then check whether GCC is installed on your system by entering the following command from the command line −
$ g++ -v
If you have installed GCC, then it should print a message such as the following −
Using built-in specs. Target: i386-redhat-linux Configured with: ../configure --prefix=/usr ....... Thread model: posix gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)
If GCC is not installed, then you will have to install it yourself using the detailed instructions available at https://gcc.gnu.org/install/
Mac OS X Installation
If you use Mac OS X, the easiest way to obtain GCC is to download the Xcode development environment from Apple's website and follow the simple installation instructions.
Xcode is currently available at developer.apple.com/technologies/tools/.
Windows Installation
To install GCC at Windows you need to install MinGW. To install MinGW, go to the MinGW homepage, www.mingw.org, and follow the link to the MinGW download page. Download the latest version of the MinGW installation program which should be named MinGW-<version>.exe.
While installing MinGW, at a minimum, you must install gcc-core, gcc-g++, binutils, and the MinGW runtime, but you may wish to install more.
Add the bin subdirectory of your MinGW installation to your PATH environment variable so that you can specify these tools on the command line by their simple names.
When the installation is complete, you will be able to run gcc, g++, ar, ranlib, dlltool, and several other GNU tools from the Windows command line.
When we consider a C++ program, it can be defined as a collection of objects that communicate via invoking each other's methods. Let us now briefly look into what a class, object, methods, and instant variables mean.
Object − Objects have states and behaviors. Example: A dog has states - color, name, breed as well as behaviors - wagging, barking, eating. An object is an instance of a class.
Class − A class can be defined as a template/blueprint that describes the behaviors/states that object of its type support.
Methods − A method is basically a behavior. A class can contain many methods. It is in methods where the logics are written, data is manipulated and all the actions are executed.
Instance Variables − Each object has its unique set of instance variables. An object's state is created by the values assigned to these instance variables.
C++ Program Structure
Let us look at a simple code that would print the words Hello World.
#include <iostream> using namespace std; // main() is where program execution begins. int main() { cout << "Hello World"; // prints Hello World return 0; }
Let us look at the various parts of the above program −
The C++ language defines several headers, which contain information that is either necessary or useful to your program. For this program, the header <iostream> is needed.
The line using namespace std; tells the compiler to use the std namespace. Namespaces are a relatively recent addition to C++.
The next line '// main() is where program execution begins.' is a single-line comment available in C++. Single-line comments begin with // and stop at the end of the line.
The line int main() is the main function where program execution begins.
The next line cout << "Hello World"; causes the message "Hello World" to be displayed on the screen.
The next line return 0; terminates main( )function and causes it to return the value 0 to the calling process.
Compile and Execute C++ Program
Let's look at how to save the file, compile and run the program. Please follow the steps given below −
Open a text editor and add the code as above.
Save the file as: hello.cpp
Open a command prompt and go to the directory where you saved the file.
Type 'g++ hello.cpp' and press enter to compile your code. If there are no errors in your code the command prompt will take you to the next line and would generate a.out executable file.
Now, type 'a.out' to run your program.
You will be able to see ' Hello World ' printed on the window.
$ g++ hello.cpp $ ./a.out Hello World
Make sure that g++ is in your path and that you are running it in the directory containing file hello.cpp.
You can compile C/C++ programs using makefile. For more details, you can check our 'Makefile Tutorial'.
Semicolons and Blocks in C++
In C++, the semicolon is a statement terminator. That is, each individual statement must be ended with a semicolon. It indicates the end of one logical entity.
For example, following are three different statements −
x = y; y = y + 1; add(x, y);
A block is a set of logically connected statements that are surrounded by opening and closing braces. For example −
{
cout << "Hello World"; // prints Hello World
return 0;
}
C++ does not recognize the end of the line as a terminator. For this reason, it does not matter where you put a statement in a line. For example −
x = y; y = y + 1; add(x, y);
is the same as
x = y; y = y + 1; add(x, y);
C++ Identifiers
A C++ identifier is a name used to identify a variable, function, class, module, or any other user-defined item. An identifier starts with a letter A to Z or a to z or an underscore (_) followed by zero or more letters, underscores, and digits (0 to 9).
C++ does not allow punctuation characters such as @, $, and % within identifiers. C++ is a case-sensitive programming language. Thus, Manpower and manpower are two different identifiers in C++.
Here are some examples of acceptable identifiers −
mohd zara abc move_name a_123 myname50 _temp j a23b9 retVal
C++ Keywords
The following list shows the reserved words in C++. These reserved words may not be used as constant or variable or any other identifier names.
| asm | else | new | this |
| auto | enum | operator | throw |
| bool | explicit | private | true |
| break | export | protected | try |
| case | extern | public | typedef |
| catch | false | register | typeid |
| char | float | reinterpret_cast | typename |
| class | for | return | union |
| const | friend | short | unsigned |
| const_cast | goto | signed | using |
| continue | if | sizeof | virtual |
| default | inline | static | void |
| delete | int | static_cast | volatile |
| do | long | struct | wchar_t |
| double | mutable | switch | while |
| dynamic_cast | namespace | template |
Trigraphs
A few characters have an alternative representation, called a trigraph sequence. A trigraph is a three-character sequence that represents a single character and the sequence always starts with two question marks.
Trigraphs are expanded anywhere they appear, including within string literals and character literals, in comments, and in preprocessor directives.
Following are most frequently used trigraph sequences −
| Trigraph | Replacement |
|---|---|
| ??= | # |
| ??/ | \ |
| ??' | ^ |
| ??( | [ |
| ??) | ] |
| ??! | | |
| ??< | { |
| ??> | } |
| ??- | ~ |
All the compilers do not support trigraphs and they are not advised to be used because of their confusing nature.
Whitespace in C++
A line containing only whitespace, possibly with a comment, is known as a blank line, and C++ compiler totally ignores it.
Whitespace is the term used in C++ to describe blanks, tabs, newline characters and comments. Whitespace separates one part of a statement from another and enables the compiler to identify where one element in a statement, such as int, ends and the next element begins.
Statement 1
int age;
In the above statement there must be at least one whitespace character (usually a space) between int and age for the compiler to be able to distinguish them.
Statement 2
fruit = apples + oranges; // Get the total fruit
In the above statement 2, no whitespace characters are necessary between fruit and =, or between = and apples, although you are free to include some if you wish for readability purpose.
Program comments are explanatory statements that you can include in the C++ code. These comments help anyone reading the source code. All programming languages allow for some form of comments.
C++ supports single-line and multi-line comments. All characters available inside any comment are ignored by C++ compiler.
C++ comments start with /* and end with */. For example −
/* This is a comment */ /* C++ comments can also * span multiple lines */
A comment can also start with //, extending to the end of the line. For example −
#include <iostream> using namespace std; main() { cout << "Hello World"; // prints Hello World return 0; }
When the above code is compiled, it will ignore // prints Hello World and final executable will produce the following result −
Hello World
Within a /* and */ comment, // characters have no special meaning. Within a // comment, /* and */ have no special meaning. Thus, you can "nest" one kind of comment within the other kind. For example −
/* Comment out printing of Hello World: cout << "Hello World"; // prints Hello World */
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