W.B Ean - C++ In One Day: The Ultimate Beginners Guide To C++ With 7 Awesome Projects

When you write a C++ program, it is compiled to a binary file that runs along with the operating system. Second, it is standard. C++ has a very well defined standard from beginning to end and this means that, if the programmer writes code in standard C++, it can be ported to other compilers with minimum or small changes. However, not everything is as simple as its sounds. Although C++ is very fast, it is very difficult to master due to the libraries that it has and the Standard Template Library (STL) that will be discussed in later chapters. But lets get started with the basics of the language.

Instructions and compiler Through the article we will be using the GNU C++ compiler, G++, along with the IDE CodeLite. All of the code will be written in standard C++. CodeLite and the compiler can be downloaded from http://downloads.codelite.org/ Libraries The full extension of C++ has libraries for many purposes: input and output, math, memory management, time, file processing, string processing and many more features. However, when we start to code, we must define which of these libraries we want to use in our program. Since 2003, C++ also implemented a feature named namespaces , which are another way to organize all of the stuff inside the language. The main function In C++, all programs must contain a function (or a piece of code) named main .

The purpose of this function is to indicate the compiler where will the program start its execution. Input and Output (I/O) Almost every program in C++ needs an input and an output. There are some exceptions to the rule, but normally, there is always I/O. The input is all the data that enters the computer, like numbers, words. The output are the data that is showed to the screen (also named console). The library used in C++ for this operations is named iostream .

Inside iostream, there are two objects that we will be using to read data from the keyboard and showing data to the console: cout and cin . Before programming anything, in CodeLite we must create a new project. Steps for creating a new project in CodeLite:

• In the main screen you will see a button with the text NEW. Click it.
• When the new window appears, select on the left side the option Console and select Simple executable (g++) from the list.
• On the right panel choose a name for your project, for example Example1.
• In project path, select a folder in your computer where you will save your code.
• In the compiler section, be sure to have gnu g++ selected.
• Click OK

This is the file where you will write your C++ code. The example code for a simple input and output in C++ is as following: #include using namespace std; int main() { cout << "This is my first C++ program"; return 0; } As you can appreciate, the first line we included the library for I/O. On the second line, using namespace std we say to C++ that we want to use all of the features inside the selected libraries (like cout ). After this, we find our main function. Here is where all the execution begins. All functions in C++ hace an opening and closing brace that indicates where the function starts and ends.

Inside main, there is the line cout << This is my first C++ program; This line will output everything inside the double quotes to the console. Notice that this line ends with a semicolon. In C++, all the instructions inside a block of code end with a semicolon (there are some exceptions that will be covered). You can see that between the cout object and our text, there are two < signs. They are named overloaded operators and they represent the direction where the information is traveling, in this case the information is going outside the computer. As you may think, when we want to make an input to the program, we will be using the >> operators.