Reading string input in Java - Cheat Sheet & Quick Revision

Recall & Review

beginner

What class in Java is commonly used to read string input from the user?

The <strong>Scanner</strong> class is commonly used to read string input from the user in Java.

beginner

How do you create a Scanner object to read input from the keyboard?

You create it with: Scanner scanner = new Scanner(System.in); This connects the Scanner to the keyboard input.

beginner

Which Scanner method reads a whole line of text including spaces?

The method nextLine() reads the entire line of input including spaces until the user presses Enter.

beginner

What happens if you use next() instead of nextLine() to read a string?

next() reads only the next word (up to the first space), not the whole line.

intermediate

Why should you close the Scanner object after use?

Closing the Scanner with scanner.close(); frees system resources and avoids resource leaks.

Which method reads a full line of user input including spaces?

A input()

B next()

C nextLine()

D readLine()

nextLine() reads the entire line including spaces until Enter is pressed.

How do you create a Scanner to read from the keyboard?

A Scanner scanner = new Scanner(System.in);

B Scanner scanner = new Scanner(System.out);

C Scanner scanner = new Scanner(System.err);

D Scanner scanner = new Scanner(System.in.read());

You must use System.in to read input from the keyboard.

What does next() method read from input?

A The next word (up to space)

B The entire line

C The next character

D Nothing, it throws error

next() reads the next token (word) separated by whitespace.

Why is it important to close a Scanner object?

A To speed up input reading

B To free system resources

C To clear the input buffer

D It is not important

Closing Scanner frees resources and prevents resource leaks.

Which import statement is needed to use Scanner?

A import java.util.Input;

B import java.io.Scanner;

C import java.lang.Scanner;

D import java.util.Scanner;

Scanner is part of the java.util package.

Explain how to read a full line of string input from the user in Java.

Think about connecting Scanner to keyboard and reading the entire line.

What is the difference between next() and nextLine() methods in Scanner?

Consider how spaces affect what each method reads.