added C++ implementation of the 0/1 Knapsack

[DiptanshuG]

Hi there,

I hope you're doing well! I wanted to participate in Hacktoberfest and contribute to your repository. I've added a C++ implementation of the Knapsack Problem, which I believe could be a valuable addition to your project.

Contribution Summary:

• Added a C++ implementation of the Knapsack Problem.
• Included a knapsack function for solving the problem.
• Provided a sample use case in the main function.

You can review the code and test it by running the provided sample in the main function.

Link to Issue (if applicable):
(Insert link to any relevant issue if you discussed this contribution in an issue)

Motivation:
The Knapsack Problem is a classic optimization problem, and having a ready-made implementation can be beneficial for developers looking to solve similar problems. This addition can be a helpful resource for the community using your repository.

Test and Verification:
I've tested the code to ensure it works as expected. It correctly calculates the maximum value within the given knapsack capacity.

Request for Review:
I kindly request you to review this pull request at your earliest convenience. Any feedback or suggestions for improvement are highly appreciated.

Thank you for considering my contribution! I look forward to hearing your thoughts on this.

Best regards,
Diptanshu Bhawsar