C++ User Input

C++ User Input

You have already learned that cout is used to output (print) values. Now we will use cin to get user input.

cin is a predefined variable that reads data from the keyboard with the extraction operator (>>).

In the following example, the user can input a number, which is stored in the variable x. Then we print the value of x:

Example

int x;
cout << "Type a number: "; // Type a number and
press enter
cin >> x; // Get user
input from the keyboard
cout << "Your number is: " << x;
// Display the input value

Note: Good To Know cout is pronounced "see-out". Used for output, and uses the insertion operator (<<) cin is pronounced "see-in". Used for input, and uses the extraction operator (>>)

Creating a Simple Calculator

In this example, the user must input two numbers. Then we print the sum by calculating (adding) the two numbers:

Example

  int x, y;
int sum;
cout << "Type a number: ";
cin >> x;
cout << "Type another number: ";
cin >>
  y;
sum = x + y;
cout << "Sum is: " << sum;

There you go! You just built a basic calculator!

Complete Reference

Tip: Both cin and cout belongs to the <iostream> library, which is short for standard input / output streams. For a complete reference of objects along with detailed information, go to our C++ iostream Reference.