Java input output

In this, tutorial we will learn how to take input from a user and how to print output in java


Output:

In java to print output we use these three statements:

System.out.println();
System.out.print();
System.out.printf();

Here,

System: is a class in the java.lang package.

out: is a static member of the System class and it is an instance of java.io.printStrem so we can say it’s  a reference  variable

print:  it is a print method It prints string inside the quotes


What is the different between println, printf,print:

println();

 The println(“…”) method prints the string   inside the quotes “…” and moves the cursor to a new line or it start printing next statement in a new line

Example

class Println {
    public static void main(String[] args) {
    	
        System.out.println("1. codeelife ");
        System.out.println("2. codeelife ");
    }
}
1. codeelife 
2. codeelife 

print();

The print(“…”) method instead prints just the string inside the quotes”…”, but does not move the cursor to a new line. Or it starts printing the next statement on the same line

Example:

class Print {
    public static void main(String[] args) {
    	
        System.out.println("1. codeelife ");
        System.out.println("2. codeelife ");
    }
}
1. print 2. print

printf();

it provides string formatting (similar to printf in C/C++ programming). It’s used to print formatted strings using various format specifiers.

How to print variable:

Let int i is an integer variable which contains value 2

int i = 2;

We print i like this

System.out.println(i);

Here you Notice that we do not use the quotation marks

System.out.println(“i”) ;  ❌this is wrong

See full example:

class Variables {
    public static void main(String[] args) {
    	
        Double number = -10.6;
    	
        System.out.println(5);
        System.out.println(number);
    }
}
5
-10.6

Note: To display integers, variables and so on, we don’t use quotation marks.


Input:

It’s very interesting to learn how to take input from the user

Let’s understand

To take input from user we use object of scanner class

Note: To use Scanner class first we have to import java.utill.Scanner package

How to create an object of the scanner and take input:

// 1st create an object of Scanner
Scanner input = new Scanner(System.in);

// 2nd take input from the user
int number = input.nextInt();

In scanner class there are different method for different input

For example

To take input as integer we use nextInt() method of scanner class

Similarly:

For long =  nextLong();

For float = nextFloat();

For double = nextDouble();

String = next();

At the end

It is a good habit to close scanner object

To this, we use the close() method after taking input

See following example:

import java.util.Scanner;

class Input {
    public static void main(String[] args) {
    	
        Scanner input = new Scanner(System.in);
    	
        // Getting float input
        System.out.print("Enter float: ");
        float myFloat = input.nextFloat();
        System.out.println("Float entered = " + myFloat);
    	
        // Getting double input
        System.out.print("Enter double: ");
        double myDouble = input.nextDouble();
        System.out.println("Double entered = " + myDouble);
    	
        // Getting String input
        System.out.print("Enter text: ");
        String myString = input.next();
        System.out.println("Text entered = " + myString);
    }
}
Enter float: 2.343
Float entered = 2.343
Enter double: -23.4
Double entered = -23.4
Enter text: Hey!
Text entered = Hey!



SHARE THIS PAGE





Important Link