String input and output in C++ - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the simplest way to read a whole line of text from the user in C++?

Use std::getline(std::cin, variableName); to read a full line including spaces until the user presses Enter.

beginner

How do you print a string variable named name to the console in C++?

Use std::cout << name << std::endl; to display the string followed by a new line.

intermediate

What is the difference between std::cin >> str; and std::getline(std::cin, str);?

std::cin >> str; reads input only until the first space, while std::getline(std::cin, str); reads the entire line including spaces.

intermediate

How can you clear the input buffer before using std::getline after std::cin >>?

Use std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n'); to discard leftover characters including the newline.

beginner

Why is it important to include #include <string> when working with strings in C++?

Because the <code>std::string</code> class is defined in the <code>string</code> header, so including it allows you to use string variables and functions.

Which function reads a full line of text including spaces in C++?

A std::getline

B std::cin >>

C std::cout

D std::printf

std::getline reads the entire line including spaces until Enter is pressed.

What happens if you use std::cin >> str; to read a string with spaces?

A It reads the whole line including spaces

B It causes a compile error

C It clears the input buffer

D It reads only up to the first space

std::cin >> str; stops reading at the first space.

How do you print a string variable name followed by a new line?

A std::getline(std::cin, name);

B std::cin >> name;

C std::cout << name << std::endl;

D printf(name);

std::cout << name << std::endl; prints the string and moves to a new line.

Which header file must you include to use std::string?

A #include &lt;string&gt;

B #include &lt;iostream&gt;

C #include &lt;vector&gt;

D #include &lt;cmath&gt;

std::string is defined in the string header.

What does std::cin.ignore() do before using std::getline?

A Prints output

B Clears leftover input including newline

C Reads a string

D Ends the program

std::cin.ignore() discards leftover characters so std::getline works correctly.

Explain how to read a full line of text from the user and then print it in C++.

Think about reading input with spaces and printing it out.

Describe the difference between using std::cin >> and std::getline for string input.

Consider how spaces affect input reading.