Scala Programming: Create a new string which is n copies of a given string

Last update on February 05 2025 12:53:34 (UTC/GMT +8 hours)

Write a Scala program to create a new string which is n (non-negative integer ) copies of a given string.

Pre-Knowledge (Before You Start!)

Before attempting this exercise, make sure you understand the following concepts:

String Manipulation: Learn how to manipulate strings, including repetition operations.
String Multiplication: Scala allows repeating a string using the * operator (e.g., "Scala" * 3 results in "ScalaScalaScala").
Function Parameters: Understand how to pass and use multiple parameters in a function.
Loop or Built-in Methods: While this exercise uses the * operator, a loop or recursion could also be used to concatenate strings multiple times.

Hints (Try Before Looking at the Solution!)

Consider the following hints to guide you through solving this exercise:

Hint 1: Use the * operator to repeat a string n times.
Hint 2: If n is 0, the function should return an empty string.
Hint 3: Consider edge cases, such as when n is 1 (it should return the original string).
Hint 4: Ensure that n is always a non-negative integer before using the repetition operation.

Sample Solution:

Scala Code:

// Define an object named scala_basic
object scala_basic {
  // Define a function named test with parameters str1 of type String and n of type Int, returning a String
  def test(str1: String, n: Int): String = {
    // Repeat the string str1 n times using the * operator
    str1 * n
  }

  // Define the main method, which is the entry point of the program
  def main(args: Array[String]): Unit = {
    // Print the result of calling test with the arguments "Scala" and 2
    println("Result: " + test("Scala", 2))

    // Print the result of calling test with the arguments "Python" and 1
    println("Result: " + test("Python", 1))

    // Print the result of calling test with the arguments "JS" and 6
    println("Result: " + test("JS", 6))
  }
}

Sample Output:

Result: ScalaScala
Result: Python
Result: JSJSJSJSJSJS

Explanation:

Here is the break down of the said Scala code:

object scala_basic {: This declares an object named scala_basic.
def test(str1: String, n: Int): String = {: This line defines a function named test that takes two parameters (str1 of type String and n of type Int) and returns a String.
str1 n: This line uses the operator to repeat the string str1 n times, creating a new string.
}: Closes the test function.
def main(args: Array[String]): Unit = {: This line defines the main method, which is the entry point of the program. It takes an array of strings (args) as its parameter and returns Unit (similar to void in other languages).
println("Result: " + test("Scala", 2)): This line calls the "test()" function with the arguments "Scala" and 2, and prints the result to the console.
println("Result: " + test("Python", 1)): Another call to the "test()" function with the arguments "Python" and 1.
println("Result: " + test("JS", 6)): Another call to the "test()" function with the arguments "JS" and 6.

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