Reading and Concatenating Strings in Java

2 min read

Problem: The Formal Greeting

Objective: Write a program that takes two names from the user and outputs a single, formatted greeting sentence. This task is a fundamental exercise in handling string input and using the concatenation operator.

Problem Statement:

Take two names, A (Speaker) and B (Recipient), as input from the user. Print the sentence: “A says Hi to B” (without the quotation marks), where A and B are the names provided in the input.

Constraint	Value
Input A & B Length	`1 ≤ length ≤ 15`
Characters	Lowercase English Alphabets

Example:

Input	Output
Input A: Ram Input B: Shyam	Output: Ram says Hi to Shyam

Solution in Java

This solution requires the Scanner class to read the input and uses System.out.println() with the + operator for output formatting.

1. Code

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        // Step 1: Initialize the Scanner object to read user input.
        Scanner sc = new Scanner(System.in);

        // Step 2: Read the first name (Speaker A).
        // sc.next() reads the next word (token) from the input.
        String nameA = sc.next();

        // Step 3: Read the second name (Recipient B).
        String nameB = sc.next();
        
        // Close the scanner when done (good practice).
        sc.close();

        // Step 4: Print the final formatted string using concatenation.
        // We combine the variable 'nameA', the fixed string " says Hi to ", 
        // and the variable 'nameB'.
        System.out.println(nameA + " says Hi to " + nameB);
    }
}

2. Explanation

Step	Concept	Description
`import java.util.Scanner;`	Input Utility	Imports the `Scanner` class, which is necessary for reading input from the console.
`Scanner sc = new Scanner(System.in);`	Scanner Object	Creates an instance of the `Scanner` object, preparing the program to listen for input.
`String nameA = sc.next();`	Reading String Input	The `sc.next()` method reads the first token (word) of input and stores it in the `String` variable `nameA`.
`String nameB = sc.next();`	Reading Second Input	Reads the second input word and stores it in `nameB`.
`nameA + " says Hi to " + nameB`	String Concatenation	The `+` operator is used here exclusively for string concatenation (joining strings and variables together) to form the required output sentence.
`System.out.println()`	Output	Prints the complete, concatenated sentence to the console, followed by a newline.