Challenge: Define a Class that Performs Operations on a String

Implement a String class that contains the following functions:

• A constructor to store the string.

• An overloaded += operator function to perform string concatenation.

• The toLower() method to convert uppercase letters to lowercase.

• The toUpper() method to convert lowercase letters to uppercase.

• The getString() method to return the stored string.

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• Input: We use the string as input.

• Output: We get the stored string from the class, convert the uppercase string to lowercase, the lowercase string to uppercase, and concatenate two strings.