Lab Reading a String From the Console

Lab Objective:

In this lab, you will demonstrate how to prompt the user to input a string and then read the string from console input.

Instructions

When you are developing console applications using Java, you must read input from users through the console. To read a string from the console as input in Java applications, you can use the Scanner class along with System.in.

Example 1 – Read String from Console Input

In this example, we shall define a scanner with the input stream, System.in. System.in creates a standard input stream that is already open and ready to supply input data. The Scanner is a simple text scanner that can parse primitive types and strings using regular expressions. So, passing System.in to Scanner allows us to parse or read strings from the standard input stream, which is the console.

public class ReadingStringFromConsole {
   public static void main(String[] args) {
       Scanner input = new Scanner(System.in);
       System.out.print("Enter three words separated by spaces: ");
       String s1 = input.next();
       String s2 = input.next();
       String s3 = input.next();
       System.out.println("s1 is " + s1);
       System.out.println("s2 is " + s2);
       System.out.println("s3 is " + s3);
   }
}

When the program is run, the execution waits after printing “Enter three words separated by spaces:,” where the user would enter a string similar to “hello world” as shown in the following console window. The program prints the string read from the console input in the next step. The whole output in the console would be as shown in the following.

Enter three words separated by spaces: Hello Java Learners
s1 is Hello
s2 is Java
s3 is Learners

Example 2: Reading a String From the Console

public class ReadingStringFromConsole {
   public static void main(String[] args) {
       Scanner input = new Scanner(System.in);
       System.out.print("Enter a character: ");
       String s = input.nextLine();
       char ch = s.charAt(0);
       System.out.println("The character entered is " + ch);
   }
}

Output

Enter a character: Perscholas
The character entered is P