If a program tries to access a variable that was defined locally in another part of the program (such as inside a different function or block), it will generally result in an error or failure to access that variable. This is because local variables have a limited scope, meaning they are only accessible within the function or block where they are defined.
Explanation of Variable Scope
- Local variables are created within a function or block and only exist during the execution of that function or block. Once the function exits, the local variable ceases to exist and cannot be accessed outside
- Trying to access a local variable from outside its defining function or block usually causes a compilation error or runtime error, depending on the language. For example, in C, attempting to use a local variable outside its function results in a compilation error because the variable is not known there
- In languages with lexical (static) scope, a variable's scope is limited to the block or function where it is declared, so other functions cannot see or use it
- In Python, accessing a local variable from another function leads to a
NameErrorbecause the variable is not defined in the global scope or the calling function's scope
- Global variables, by contrast, are accessible from anywhere in the program, which is why variables defined outside functions can be accessed inside functions unless shadowed by a local variable
Summary
- If a program tries to access a variable defined locally in another part of the program, it will not be able to access it due to scope restrictions.
- This results in errors such as compilation errors in compiled languages (e.g., C) or runtime errors like
NameErrorin interpreted languages (e.g., Python). - To share data between parts of a program, variables must be declared with a broader scope (e.g., global scope) or passed explicitly as parameters.
This behavior enforces modularity and prevents unintended side effects by restricting variable visibility to where it is logically relevant
