Data output to the screen and keyboard input

Data output to the screen and keyboard input
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data output and data inputFirst, let's talk about the data output to a monitor, since you, partly, since it faced in previous lessons. As you remember, using the key words cout, we can bring to the monitor line, which we write in “quotes”, or the value of the variable, referring to her by name . As you are familiar with the operator endl, which allows you to convert the output to the next line. And another important point – we can combine the output data using the operator << several times after cout:

cout << “The value of the variable var_name = ” << var_name << endl;

Now we meet with several special character sequences, which will help us to manipulate the data output to the screen. Here is a list:

output, basics of programming
Fig.1 – Character sequences, output

You look and think ))) Why use a backslash? Consider the example. We need to display a quote from the film. Just let the alarm sounds, which will attract the user's attention on the screen. Centered will place the title and name of the film, from which we quote, and lower – quote.At screen should look like this:


Try to dial the code yourself! The solution below:

Why do we need a backslash? It tells the compiler: “Attention, for me is not just a symbol, and a special! He will tell you, what should be done! :)” That line 8, if we did not use you backslash, the screen would go to five characters and a conclusion. А так, we hear “great music”. In string 9 also interesting: two tabs, Further it is necessary to display a back slash, but in fact it is necessary to write two, well, take the name of the movie in quotes. At the end of each line instead of the flow manipulator endl (<< endl) which allows go to a new line (actually an analogue of the Enter key your keyboard) more convenient and shorter, in this case, use the control symbol \n.

Now let's talk about how to enter data from the keyboard by the user. We already know – to assign a value to a variable, it can be initialized when you create or assign a value to the downstream program: name of variable = value; And now we learn to write down in the value of a variable, which introduces the user with the keyboard. We can organize the data entry operators using cin and >> . The syntax is: cin >> nameofvariable. Consider an example of this opportunity:

Run the program and note – program will command the 11-th row and, reaching the operator cin >>, stop and start waiting for action from the user. It is necessary to enter the value and press Enter. Once the variable has the value, Permission from the keyboard, the program will continue execution.

data input

It is worth noting, what cin understand and distinguish between the types of variables. And if you type in int symbol, rather than the figure, value of the variable does not change. And if you enter an invalid value in a variable, which is not initialized when you create, is displayed on the screen any residual “garbage” of variable. To enter characters – Variables need to be declared type char. We will soon learn how to you to check user input is correct. And also learn how to enter the keyboard is not a single character, and the whole line.

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22 thoughts on “Data output to the screen and keyboard input

  1. I wrote the following code:

    int amount_of_apples1=0;
    int amount_of_apples2=0;
    int inBox = 0; //recording the total amount of
    cin >> amount_of_apples1;
    cin >> amount_of_apples2;

    When the program starts, to a request entered is not a number but a string, it is clear that the value has not changed amount_of_apples1, remained 0. But this statement cin >> amount_of_apples2 was ignored, why. Meaning amount_of_apples2 not request and therefore remains too 0.

  2. #include
    using namespace std;

    int main()


    cout << " Why is it in a restaurant will never like it,\n";
    cout << " She ordered that the, and always like what I ordered?\n";
    cout << " And she begins to eat from my plate. I tell her:\n";
    cout << " <>.She says:<< What for?\n";
    cout <>.And eats half. N”;
    cout << " \t\t\\к.ф.\"О чем говорят мужчины\" \\ \n";

    return 0;


    3 exercise made

  3. Why when I run the program instead of ordinary letters gets some sort of incomprehensible garbage?

    1. And because, when you want to answer the question, this “garbage” We need to show (copy), not to talk about it “on fingers”.

  4. fatal error C1083: Can not open file inclusion: iostrem: No such file or directory
    What to do?

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