Learn to code in C++ (lesson 3) - comments

You should now have a pretty good handle on outputting text to your display. But before we move onto "bigger things", we quickly need to touch on comment statements. Comment statements are any statements that begin with //. When C++ sees //, the compiler with automatically ignore everything after the // on that line. You might be wondering why you would want to include any "code" that is totally ignored. Well, remember when we spoke about good programming style? It is good practice to include comments in your program explaining what the program does (or even what parts of your program do). As an example, it is best practice to include a comment statement at the whole beginning of your program letting another programmer know what the program actually does. Like this:

//Display "Hello World" on the screen
#include <iostream>
using namespace std;
int main()
{
    cout << "Hello, World!";
    return 0;
}

Going forward, make sure that you use a comment statement at the beginning of all your programs explaining the purpose of your program. Remember, everything after the // on that line is ignored. Take this program as an example:

//Display text on different lines
#include <iostream>
using namespace std;
int main()
{
    cout << "Line 1" << endl;
    cout << "Line 2";
    return 0;
}

The output would be:

Line 1
Line 2

Now we add // before the first cout statement:

//Display text on different lines
#include <iostream>
using namespace std;
int main()
{
    //cout << "Line 1" << endl;
    cout << "Line 2";
    return 0;
}

Now the first cout statement is totally ignored thus the output would be:

Line 2

I hope you understand the importance of comments statements and how useful they can be. You will see that we will be using these a lot as our programs start to grow 😎

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