Each question must be at least 2 paragraphs and C++

1. Let's start with the basics: What is an array? What is it useful for? 

2. The goal of introducing classes is to render support to the practices of object-oriented programming and eliminate the drawbacks caused by using smaller units of modularity: functions. The primary goal of the class construct is to bind together data and operations into one syntactical unit, and to indicate that these coding elements belong together. What are classes and objects? What is the relationship between them? Please provide a real-world example that demonstrates this relationship. 

3. Let's start at the very beginning. What is a file? Why is it necessary to "open" and "close" a file? What happens when we do that?