Question

If a function is defined as static, it means

• A. The value returned by the function does not change
• B. all the variable declared inside the function automatically will be assigned initial value of zero
• C. It should be called only within the same source code program file.
• D. None of the other choices as it is wrong to add static prefix to a function

Hint:

Using static on functions is a common and excellent practice in C programming to hide helper functions from the global scope, effectively achieving a form of encapsulation.

Answer 1

The Correct Option is C

Step 1: Understanding the Question:
We need to identify the specific behavior or restriction that applies to a function when it is defined with the static keyword in languages like C or C++.


Step 2: Detailed Explanation:
In programming languages like C and C++, the static keyword has multiple specific uses depending on its context (variables vs. functions).
When the static keyword is applied to a global function definition, it changes the function's linkage type from external linkage to internal linkage.
This restricts the scope and visibility of the function exclusively to the translation unit or the specific source code file in which it is declared.
Consequently, it cannot be accessed or called from other separate program files, which helps prevent naming conflicts in large, multi-file projects.


Step 3: Final Answer:
It should be called only within the same source code program file.

Answer 2

The question asks what it means when a function is declared with the static keyword. Let's evaluate each option on its own merits.

1. The value returned by the function does not change: The static keyword has no effect on what a function returns or how its return value behaves between calls; a static function can still return different values on different calls depending on its logic and arguments. This option confuses static with something like a constant return, which is not what static means here.
2. All the variables declared inside the function automatically will be assigned initial value of zero: Zero-initialization is a real behavior, but it applies to a variable declared as static inside a function (a static local variable retains its value and defaults to zero if uninitialized), not to the function itself being declared static. This option describes a different, unrelated use of the same keyword.
3. It should be called only within the same source code program file: Declaring a function static changes its linkage from external to internal, meaning the compiler and linker restrict its visibility to the file it is defined in. Other source files in the same project cannot call it, which is exactly what this option states.
4. None of the other choices, as it is wrong to add static prefix to a function: This is incorrect because static is a completely valid and commonly used prefix for functions in C and C++; there is nothing improper about writing a static function.

Since static specifically restricts a function's visibility to its own source file by giving it internal linkage, the option describing that restriction is the accurate one.

Therefore, the correct answer is It should be called only within the same source code program file.