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- - - - cin is the standard input by default is the keyboard
        
        In C++, a new-line character can be specified as \n
- - - - For formatted output operations, cout is used together with the insertion operator, which is written as << (i.e., two "less than" signs).
      - For formatted input operations, cin is used together with the extraction operator, which is written as >> (i.e., two "greater than" signs).
        
        The extraction operator can be used on cin to get strings of characters in the same way as with fundamental data types.
        
        However, cin extraction always considers spaces (whitespaces, tabs, new-line...) as terminating the value being extracted, and thus extracting a string means to always extract a single word, not a phrase or an entire sentence.
        
        To get an entire line from cin, there exists a function, called getline, that takes the stream (cin) as first argument, and the string variable as second.
      - The standard header <sstream> defines a type called stringstream that allows a string to be treated as a stream, and thus allowing extraction or insertion operations from/to strings in the same way as they are performed on cin and cout.
- - - - Additionally, cerr and clog are two other streams used for error and log outputting, respectively. cerr is used for error messages, and unlike cout, it is unbuffered and outputs immediately. clog is used for general logging messages and is buffered.
- - - - In C++, standard input/output operations are managed by the iostream library. Here are the primary objects used:
        
        Main
        
        cin: Standard input stream
        
        cout: Standard output stream
        
        cerr: Standard error output stream (for errors and diagnostics)
        
        clog: Standard logging stream (for logging non-critical information)
        
        cin: Standard input stream
        
        cout: Standard output stream
        
        cerr: Standard error output stream (for errors and diagnostics)
        
        clog: Standard logging stream (for logging non-critical information)
- - - - A stream is an entity where a program can either insert or extract characters to/from. There is no need to know details about the media associated to the stream or any of its internal specifications.
      - cin
        
        standard input stream
      - clog
        
        standard logging (output) stream
      - cout
      - cerr
        
        standard error (output) stream
- - - - The standard behavior that most users expect from a console program is that each time the program queries the user for input, the user introduces the field, and then presses ENTER (or RETURN). That is to say, input is generally expected to happen in terms of lines on console programs, and this can be achieved by using getline to obtain input from the user. Therefore, unless you have a strong reason not to, you should always use getline to get input in your console programs instead of extracting from cin.
- - - - Standard input (cin)
        
        The extraction operation on cin uses the type of the variable after the >> operator to determine how it interprets the characters read from the input; if it is an integer, the format expected is a series of digits, if a string a sequence of characters, etc.
        
        For example
        
        cout << "Hello"; // prints Hello
        cout << Hello; // prints the content of variable Hello
        
        cout << "Output sentence"; // prints Output sentence on screen
        
        cout << 120; // prints number 120 on screen
        
        cout << x; // prints the value of x on screen
        
        cout << "This " << " is a " << "single C++ statement";
        
        Standard output (cout)
        
        The << operator inserts the data that follows it into the stream that precedes it. In the examples above, it inserted the literal string Output sentence, the number 120, and the value of variable x into the standard output stream cout.
        
        For example
        
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        The standard library defines a handful of stream objects that can be used to access what are considered the standard sources and destinations of characters by the environment where the program runs:
        
        C++ uses a convenient abstraction called streams to perform input and output operations in sequential media such as the screen, the keyboard or a file.
      - cin standard input stream
      - cout standard output stream
      - cerr standard error (output) stream
      - clog standard logging (output) stream
      - Main