What is the Difference Between Instance Variable and Local Variable?
🆚 Go to Comparative Table 🆚The main difference between instance variables and local variables lies in their scope, visibility, and lifetime. Here are the key differences:
Instance Variables:
- Declared within a class but outside a method, constructor, or block.
- Visible and accessible to all constructors, methods, or blocks in the class.
- Created when an object is instantiated and destroyed when the object is destroyed.
- Accessed using the object reference.
- Must be initialized when declared, or else they will have a default value.
Local Variables:
- Declared within a method, constructor, or block.
- Visible and accessible only within the method, constructor, or block it is declared in.
- Created when a method, constructor, or block is entered and destroyed when the method, constructor, or block is exited.
- Accessed without using an object reference.
- Must be initialized before use; otherwise, it won't compile.
In summary, instance variables are associated with objects and can be accessed throughout the class, while local variables are associated with specific methods, constructors, or blocks and have a limited scope and visibility.
On this pageWhat is the Difference Between Instance Variable and Local Variable? Comparative Table: Instance Variable vs Local Variable
Comparative Table: Instance Variable vs Local Variable
Here is a table comparing the differences between instance variables and local variables:
Feature | Instance Variables | Local Variables |
---|---|---|
Definition | Variables declared within a class but outside the body of methods. | Variables declared within programming blocks, methods, or constructors. |
Scope | Accessible to all constructors, methods, or blocks in the class. | Limited to the scope of the method, block, or constructor in which they are declared. |
Memory | Stored in a table associated with the object. | Stored on the stack. |
Lifetime | Created when an object is instantiated and destroyed when the object is destroyed. | Created when a method, block, or constructor is started and destroyed once it exits the block, method, or constructor. |
Accessibility | Can be accessed directly by calling the variable name inside the class. | Can only be accessed within the specific block, method, or constructor in which they are declared. |
In summary, instance variables are associated with objects and have a more global scope within the class, while local variables are limited to the scope of the method, block, or constructor in which they are declared.
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