Java Scanner — Free Java Tutorial

TL;DR: Learn Java Scanner in Java with a free, beginner-friendly tutorial, examples and practice for Indian students on Syllab.in.

Java Scanner in Java

The Scanner class (java.util.Scanner) reads input from various sources: System.in (keyboard), files, or strings. It is the standard way to read user input in console Java programs.

Import it with: import java.util.Scanner; Then create an instance: Scanner sc = new Scanner(System.in);

Key methods: nextInt(), nextDouble(), nextLong(), next() (reads one word), nextLine() (reads entire line including spaces).

Always close the Scanner when done: sc.close(). This releases the underlying stream resource.

Common pitfall: after calling nextInt() or nextDouble(), a newline character remains in the buffer. Call sc.nextLine() to consume it before calling nextLine() again.

import java.util.Scanner;

Scanner sc = new Scanner(System.in);

int n       = sc.nextInt();      // read integer
double d    = sc.nextDouble();   // read decimal
String word = sc.next();         // read one word
String line = sc.nextLine();     // read full line

sc.close();

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