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C++ Basics #7 Basic Input and Output

Topics covered in this video:

• Standard output (cout)
• Standard input (cin)
• stringstream

What is input and output?

• Interaction with the user.
• Changing program according to user input.
• C++ uses streams to perform input and output.
• Stream is object where an object can either insert or extract characters to/from it.
• C++ have iostream file in library where the input and output streams objects are declared.

1. Standard Output (cout):
   • Default standard output is screen.
   • To give output we use ‘cout’ with << (Two less than signs)
   • Example:

     • cout << 23; 

       (gives 23 in screen)   

     • cout << x; 

       (prints the value of x to screen)

     • cout << “Hello world!”  

       (prints Hello World to   screen)

     • cout << “My age is: “ << age; 

   • Using endl or “n” will take output to next line.
2. Standard Input(cin):
   • cin is used with >> to get a input from the stream.
   • Example: cin >> VariableName(To store the input)
   • To request more than one datum we can use multiple >>
   • Example:

     cin >> data1 >> data2;

     Which is same as

     cin >> data1;
     cin >> data2;

   • When getting string with cin, it will stop taking character as soon as it gets to a blank space. Use getline() instead
   • Using same variable to get input in different places will just replace the previous value of variable with new one.
3. stringstream
   • Header file <sstream> defines the class stringstream that allows a string-based objects to be treated as a stream.
   • Especially useful to convert numerical value or string and viceversa
   • Example:

     string UserInput;
     float NumValue = 0;
     getline(cin, UserInput);
     stringstream(UserInput) >> NumValue;