Java Programming Lesson 7 Part-3 | Scanner Input (more) – Advanced Usage

 LESSON-7 PART-3

Scanner Input (more) – Advanced Usage

✅ Let’s continue Lesson-7 (Extended): Scanner Input – Advanced Usage
This will make you pro at taking inputs in Java 💪

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📘 Scanner Input — Advanced Concepts

✅ Scanner is used to take input from keyboard
✅ Located in java.util package

import java.util.Scanner;

Create Scanner object:

Scanner sc = new Scanner(System.in);

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✅ Input Types

Method	Input Type	Example
nextInt()	Integer	25
nextDouble()	Decimal number	99.5
nextBoolean()	Boolean (true/false)	true
next()	Single word string	"Java"
nextLine()	Full line string	"Java Programming Course"
nextFloat()	Float	10.55f

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✅ Example 1: Taking Different Inputs

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        System.out.print("Enter your age: ");
        int age = sc.nextInt();

        System.out.print("Enter your GPA: ");
        double gpa = sc.nextDouble();

        System.out.print("Enter your name: ");
        sc.nextLine();  // clear buffer
        String name = sc.nextLine();

        System.out.println("Name: " + name);
        System.out.println("Age: " + age);
        System.out.println("GPA: " + gpa);
    }
}

⚠️ Notice sc.nextLine() after nextInt()
This clears the buffer issue ✅

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✅ Example 2: Taking Multiple Words Using nextLine()

System.out.print("Enter address: ");
String address = sc.nextLine();

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✅ Example 3: Check Even or Odd

System.out.print("Enter a number: ");
int n = sc.nextInt();

if(n % 2 == 0) {
    System.out.println("Even Number");
} else {
    System.out.println("Odd Number");
}

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✅ Example 4: User Menu Input (Switch)

System.out.println("1. Add");
System.out.println("2. Subtract");
System.out.print("Enter your choice: ");
int choice = sc.nextInt();

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✅ Input Validation Example

System.out.print("Enter a number: ");
if(sc.hasNextInt()) {
    int num = sc.nextInt();
    System.out.println("Valid number: " + num);
} else {
    System.out.println("Invalid Input!");
}

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🔥 BONUS — Password Input with Hidden Characters (Console)

Console console = System.console();
char[] password = console.readPassword("Enter password: ");
System.out.println("Password stored securely!");

(Works when running outside IDE like Eclipse terminal)

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🧠 KEY POINTS

✔ nextLine() takes full sentence
✔ Use an extra nextLine() after numeric input
✔ Always close scanner → sc.close()
✔ Input validation using hasNextInt()

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✅ Practice Task for You

Write a program to input:

1. Full Name

2. Mobile Number

3. Age

4. Course Name

Then print in a formatted way like:

Student Profile:
Name: S.M. JITU HASAN
Mobile: 017xxxxx
Age: 21
Course: Java Programming

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✅ Lesson-7 PART-3 Completed!

➡ NEXT Lesson-8