Writing Your Very First C++ Program

We have discussed working with C++ on different operating systems, and with different IDE's, but for this guide we are going to be working exclusively in Windows and Code::Blocks. Let’s begin by writing your first C++ program and taking the first small step into a larger coding world.

It’s traditional in programming for the first code to be entered to output the words ‘Hello, World!’ to the screen. Interestingly, this dates back to 1968 using a language called BCPL.

Step 1 – As mentioned, we’re using Windows 10 and the latest version of Code::Blocks for the rest of the C++ code in this book. Begin by launching Code::Blocks. When open, click on File > New > Empty File or press Ctrl+Shift+N on the keyboard.

Step 2 – Now you can see a blank screen, with the tab labelled *Untitled1, and the number one in the top left of the main Code::Blocks window. Begin by clicking in the main window, so the cursor is next to the number one, and entering:

#include <iostream>

Step 3 – At the moment it doesn’t look like much, and it makes even less sense, but we’ll get to that in due course. Now click on File > Save File As. Create or find a suitable location on your hard drive and in the File Name box, call it helloworld.cpp. Click the Save as type box and select C/C++ files. Click the Save button.

Step 4 – You can see that Code::Blocks has now changed the colour coding, recognising that the file is now C++ code. This means that code can be auto-selected from the Code::Blocks repository. Delete the #include <iostream> line and re-enter it. You can see the auto-select boxes appearing.

Step 5 – Auto-selection of commands is extremely handy and cuts out potential mistyping. Press Return to get to line 3, then enter:

int main()

Note: there’s no space between the brackets.

Step 6 – On the next line below int main(), enter a curly bracket:


This can be done by pressing Shift and the key to the right of P on an English UK keyboard layout.

Step 7 – Notice that Code::Blocks has automatically created a corresponding closing curly bracket a couple of lines below, linking the pair, as well as a slight indent. This is due to the structure of C++ and it’s where the meat of the code is entered. Now enter:

//My first C++ program

Step 8 – Note again the colour coding change. Press Return at the end of the previous step’s line, and then enter:

std::cout << “Hello, world!\n”;

Step 9 – Just as before, Code::Blocks auto-completes the code you’re entering, including placing a closing speech mark as soon as you enter the first. Don’t forget the semicolon at the end of the line; this is one of the most important elements to a C++ program and we’ll tell you why in the next section. For now, move the cursor down to the closing curly bracket and press Return.

Step 10 – That’s all you need to do for the moment. It may not look terribly amazing but C++ is best absorbed in small chunks. Don’t execute the code at the moment as you need to look at how a C++ program is structured first; then you can build and run the code. For now, click on Save, the single floppy disc icon.

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David Hayward

David has spent most of his life tinkering with technology, from the ZX Spectrum, getting his hands on a Fujitsu VPP5000/100 supercomputer, and coding on an overheating Raspberry Pi. He's written for the likes of Micro Mart, Den of Geek, and countless retro sites and publications, covering reviews, creating code and bench testing the latest tech. He also has a huge collection of cables.

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