Tamilnadu Samacheer Kalvi 12th Computer Science Notes Chapter 3 Scoping Notes
- Scope refers to the visibility of variables, parameters and functions in one part of a program to another part of the same program.
- The scope of a variable is that part of the code where it is visible.
- The LEGB rule is used to decide the order in which the scopes are to be searched for scope resolution
- The process of binding a variable name with an object is called mapping.
- = (equal to sign) is used in programming languages to map the variable and object.
Namespaces are containers for mapping names of variables to objects.
Local scope refers to variables defined in current function.
A variable which is declared outside of all the functions in a program is known as global variable.
A function (method) with in another function is called nested function.
A variable which function which contains another function definition with in it, the inner function can also access the variable of the outer function. This scope is called enclosed scope.
Built-in scope has all the names that are pre-loaded into program scope when we start the compiler or interpreter.
- A module is a part of a program.
- Programs are composed of one or more independently developed modules.
The process of subdividing a computer program into separate sub-programs is called Modular programming.
Access control is a security technique that regulates who or what can view or use resources in a computing environment. It is a fundamental concept in security that minimizes risk to the object.
Public members (generally methods declared in a class) are accessible from outside the class.
Protected members of a class are accessible from within the class and are also available to its sub-classes.
Private members of a class are denied access from the outside the class: They can be handled only from within the class.They can be handled only from within the class.
Access Specifiers in Python and C++ and Java:
- Python prescribes a convention of prefixing the name of the variable/method with single or double underscore to emulate the behaviour of protected and private access specifiers.
- C++ and Java, control the access to class members by public, private and protected keywords
- All members in a Python class are public by default whereas by default in C++ and java all members are private.