An instance variable is typically associated with an object instance of the class whereas class variable is not associated with any object instance. Static variables are referred to as class variables while non-static regular variables are called instance variables. Simply put, you will have as many instances of the instance variable as there are object instances. i.e., if there are 10 instances of an object, you will have 10 instances of that instance variable as well. But, there will be only one instance of the static or class variable.
Instance variables are accessed as follows:
objname.variableName;
Class variables are accessed as follows:
ClassName.variableName;
In the case of an instance variable, there is one copy for every instance (object). If you create 10 objects based on a class, there will be 10 copies of the variable. A class variable exists only once for the entire class - no matter how many objects you create - or even if you create no objects based on the class. In Java, such variables (class variables) are declared with the statickeyword.
structure variable can access the variable but class object can access the function also
A data member belongs to an object of a class whereas local variable belongs to its current scope. A local variable is declared within the body of a function and can be used only from the point at which it is declared to the immediately following closing brace. A data member is declared in a class definition, but not in the body of any of the class member functions. Data members are accessible to all member function of the class.
Reference variables in java is used to refer to an object. Its a way to access another variable or memory address with a variable and change the data inside the memory address. It gives direct access to the memory access. example:- Box b=new Box(); b is the reference variable of type Box. It can hold reference to any instance of class Box. new Box() creates an instance of class Box. So b is now pointing to an object of class Box. shreya..
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Class Variable is a subset of Variables.
In the case of an instance variable, there is one copy for every instance (object). If you create 10 objects based on a class, there will be 10 copies of the variable. A class variable exists only once for the entire class - no matter how many objects you create - or even if you create no objects based on the class. In Java, such variables (class variables) are declared with the statickeyword.
structure variable can access the variable but class object can access the function also
The main difference between the class variable and Instance variable is, first time, when class is loaded in to memory, then only memory is allocated for all class variables. Usually static variables are called class variables. These variables are available throughout the execution of the application and the values are common to the class. You can access them directly without creating an object of the class. Instance variables are normal variables declared in a class, that would get initialized when you create an instance of the class. Every instance of the class would have a copy of the variable and you need a class instance (object) to access these variables
A data member belongs to an object of a class whereas local variable belongs to its current scope. A local variable is declared within the body of a function and can be used only from the point at which it is declared to the immediately following closing brace. A data member is declared in a class definition, but not in the body of any of the class member functions. Data members are accessible to all member function of the class.
The static modifier tells the system that this particular variable belongs to the class and does not belong to any specific instance of the same. The class will contain only one instance of the static variable irrespective of how many objects of the class you create.
An object is an INSTANCE of a class. Human is a class, while YOU are a person, an instance of Human class, but YOU do not represent the entire human class. Or, a class provides the abstraction, and an object is a typical example of that abstraction. Classes provide a blue print to build a real instance of an object.
hi friend.... Instance variable means with which you need to create an obeject in order to invoke any methods or variables defined in a class. For ex: class A { int a=10; public void inc() {return a++; } } To invoke a member A b=new A(); b.inc(); System.out.println(b.a); If incase of a static method you can directly call using class name itself. like : b=Math.sqrt(a);
An attribute is a class member variable while a behaviour is a class member method.
Default values are available for any class or instance variable. If you do not specify a value for a class or instance variable the JVM will provide a default value that will ensure that the system does not end up with any unexpected errors because you used a variable that was not initialized. Ex: Public class Test { int I; } In the above class we have just declared an instance variable called 'I' but we haven't associated any value to it. The JVM automatically assigns 0 as the default value to this variable.
A private variable is one that is accessible only to the current class and cannot be accessed by any other class, including the ones that extend from it. A final variable is one that cannot be modified once it is initialized and assigned a value.
In Java, there are three kinds of variables: local variables, instance variables, and class variables. Variables have their scopes. Different kinds of variables have different scopes. A variable is shadowed if there is another variable with the same name that is closer in scope. In other words, referring to the variable by name will use the one closest in scope, the one in the outer scope is shadowed.A Local Variable Shadows An Instance VariableInside a class method, when a local variable have the same name as one of the instance variable, the local variable shadows the instance variable inside the method block.