objective-c-basics.md

+https://www.tutorialspoint.com/objective_c/index.htm
+
+You should create an iOS application in Xcode, written in Objective-C. It should contain 2 classes: Organization and Employee, both of each are subclasses of NSObject. Organization should have the following properties:
+
+*  Public “name” of type NSString.
+*  Private “employees” of type NSArray<Employee>. 
+
+And the following methods: 
+
+
+*  Public initWithName initializer method, which accepts organization name as an input parameter.
+
+*  Public addEmployeeWithName: (accepts employee name as an input parameter with no return type), which creates a new employee and adds it to the array. The salary is random between 100 and 5000 and is divisible by 10 (e.g. 110, 4670).
+
+*  Public calculateAverageSalary method, which return the average salary of all employees.
+
+*  Public employeeWithLowestSalary method, which returns one employee with the lowest salary in the organization.
+
+*  Public employeesWithSalary: method, which accepts one argument of type int - salary - and returns all employees with given salary as an array.
+
+
+Employee should have the following properties:
+
+*  Private “firstName” and “lastName”, which are of type NSString.
+
+*  Public “salary” of type int.
+
+*  Public readonly property “fullName”, which returns the conjuction of first name and last name.
+And the following methods:
+
+*  Public initWithFirstName:lastName:salary: initializer method, which accepts first name, last name and salary as input parameters.
+
+Application should create one organization and multiple employees, which are added to the organization. Than all of the methods should be demonstrated. Everything should be logged to NSLog.
+
+
+You should be able to answer the following questions:
+
+1.  How could a class be defined in Objective-C?
+2.  What is a property?
+3.  What options does a property have?
+4.  What is ARC?
+5.  What is a category?
+6.  What is the difference between instance method and class method?
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