Real-life examples of using Scanner for user input in Java applications

📚 Quick Study Guide

• ⌨️ The `Scanner` class is part of the `java.util` package and is used to read input from various sources like the keyboard (System.in), files, etc.
• ⚙️ To use `Scanner`, you first need to import it: `import java.util.Scanner;`
• ✍️ Create a `Scanner` object: `Scanner scanner = new Scanner(System.in);`
• 📤 Common methods include:
  • `nextInt()`: Reads an integer.
  • `nextDouble()`: Reads a double.
  • `next()`: Reads the next token as a string.
  • `nextLine()`: Reads the entire line as a string.
  • `hasNextInt()`: Checks if the next input is an integer.
• ⚠️ Remember to close the scanner after use to prevent resource leaks: `scanner.close();`

Practice Quiz

1. Question 1: What is the primary purpose of the `Scanner` class in Java?
   1. A. To write output to the console.
   2. B. To read input from various sources.
   3. C. To create graphical user interfaces.
   4. D. To perform mathematical calculations.
2. Question 2: Which package does the `Scanner` class belong to?
   1. A. `java.io`
   2. B. `java.util`
   3. C. `java.lang`
   4. D. `java.net`
3. Question 3: Which method is used to read an integer from the input using a `Scanner` object?
   1. A. `readInt()`
   2. B. `getInt()`
   3. C. `nextInt()`
   4. D. `scanInt()`
4. Question 4: What does the `nextLine()` method do when used with a `Scanner` object?
   1. A. Reads the next word.
   2. B. Reads the entire line.
   3. C. Reads the next integer.
   4. D. Reads the next double.
5. Question 5: Why is it important to close a `Scanner` object after using it?
   1. A. To prevent memory leaks.
   2. B. To improve program speed.
   3. C. To avoid compiler errors.
   4. D. To enable garbage collection.
6. Question 6: Which method checks if the next input is an integer without actually consuming the input?
   1. A. `isInt()`
   2. B. `checkInt()`
   3. C. `hasNextInt()`
   4. D. `peekInt()`
7. Question 7: How do you create a Scanner object to read input from the keyboard?
   1. A. `Scanner scanner = new Scanner(System.out);`
   2. B. `Scanner scanner = new Scanner(System.in);`
   3. C. `Scanner scanner = new Scanner(System.err);`
   4. D. `Scanner scanner = new Scanner(System.console());`