Java's Scanner()

#java

See: Java SE 8 Documentation

Scanner is a class that allows for reading input from the user.

import java.util.Scanner;

Scanner _objName_ = new Scanner(System.in);
_dataType_ _varName_ = _objName_.next_DataType_();

Methods §

next[dataType] §

scanner_object.next[dataType] returns the corresponding value from the input. Below is an example of a program to take an integer from the user:

import java.util.Scanner;
 
public class Tester {
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		System.out.print("Enter a value please: ");
		int userInput = in.nextInt();
 
		System.out.println("You entered %d", userInput);
	}
}

hasNext[dataType] §

Will return true as long as the next input has the same dataType.

File f1 = new File("input.txt");
Scanner in = new Scanner(f1);
while(f1.hasNextLine()){
	System.out.println(f1.nextLine());
}

---

Examples §

Grading System §

import java.util.Scanner;
 
public class GradingSystem{
	public static void main(String[] args){
		Scanner in = new Scanner(System.in);
		double grade = in.nextDouble();
	}
}

For a full use of this example, see Grading System

Counting while provided input §

Scanner in = new Scanner(system.in);
int total = 0;
while (in.hasNextInt()){
	int number  = in.nextInt();
	total += number;
}