User input in java with examples

For Integer:-

import java.util.Scanner;

class group{

public static void main(String arg[]){

int num;

Scanner data = new Scanner(System.in);

System.out.println("Enter a number");

num = data.nextInt();

System.out.println("Entered number is:"+num);

}

}

Above program is simple example for user input where user enter a number which is assigned to variable num.

where Scanner takes information from user keyboard and saved in variable.For using Scanner we have to import Scanner.

Syntax for import a Scanner:-

import java.util.Scanner;

data is Scanner variable. when we press a key, data store value of that key.

num = data.nextInt();

In above line we assigning value of data to num. where num is integer so we used a commend data.nextInt() which Scans input as integer.

Scanner_variable.nextInt(); - The int scanned from the input.

Example:-

Program to find sum of 2 number.

import java.util.Scanner;

class find_sum{

public static void main(String arg[]){

int num1, num2, sum;

Scanner data = new Scanner(System.in);

System.out.println("Enter 1st number");

num1 = data.nextInt();

System.out.println("Enter 2nd number");

num2 = data.nextInt();

sum=num1+num2;

System.out.println("sum of 2 number:"+sum);

}

}

Here data is Scanner variable. int is scanned from input and assigned to num1 and num2 variables.

For Floating Point:-

Scanner_variable.nextFloat(); - The float scanned from the input

Scanner_variable.nextDouble(); - The double scanned from the input.

Example:-

Program to find sum of 2 number.

import java.util.Scanner;

class Find_sum{

public static void main(String arg[]){

double num1, num2, sum;

Scanner data = new Scanner(System.in);

System.out.println("Enter 1st number");

num1 = data.nextDouble();

System.out.println("Enter 2nd number");

num2 = data.nextDouble();

sum=num1+num2;

System.out.println("sum of 2 number:"+sum);

}

}

For Boolean:-

Scanner_variable.nextBoolean(); - The boolean scanned from the input

For Characters:-

Scanner_variable.nextLine(); - The character Scanned from the input.

Example:-

Program to display user input.

import java.util.Scanner;

class disp{

public static void main(String arg[]){

Scanner data = new Scanner(System.in);

System.out.println(data.nextLine());

}

}

or

import java.util.Scanner;

class group{

public static void main(String arg[]){

System.out.println("Enter your text");

Scanner data = new Scanner(System.in);

String text = data.nextLine();

System.out.println(text);

}

}

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