Object collaboration is one of the most important topics in OOP. If the objects don't collaborate with each other in a program, nothing can be achieved. For example, if we think about a simple web application, we can see how the relationship between different objects plays an important role in constructing the application. Twitter, for example, has many objects that are related to each other in order to make the application work. The User object consists of the username, password, first name, last name, picture, and other user-related information belonging to Twitter users. There could be another object called Tweet that consists of a message, date and time, the username of the user who posted the tweet, and some other properties. There may also be another object called Message that holds the content of the message, who it was from, who it...
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