Introduction / Context:
Functions are fundamental building blocks in C and C++ that package a sequence of statements into a named, reusable unit. A solid grasp of what functions can and cannot do is essential for modular design, maintainability, and testing. This question asks you to identify the single false statement among several common claims about functions.
Given Data / Assumptions:
- We are discussing standard C/C++ user-defined and library functions.
- Functions may return a value (non-void) or return nothing (void).
- Programs routinely call functions multiple times from various locations.
Concept / Approach:
- A function encapsulates a specific task and can be invoked whenever that task is needed.
- Good design decomposes complex problems into smaller functions for clarity and reuse.
- There is no language restriction that limits a function to a single invocation.
Step-by-Step Solution:
Scan each statement for correctness based on standard function semantics.Statements about task encapsulation, decomposition, reuse, and void/value-returning functions are all true.The claim that a function can be called only once is false. Functions can be called any number of times, including zero, once, or thousands of times.
Verification / Alternative check:
Consider a utility like max(a, b) or std::sort: these are intentionally designed to be reused and called multiple times in a single program run.
Why Other Options Are Wrong:
- A function is a block that performs a task: True for all mainstream languages.
- Breaking large problems into smaller functions: True and a core design principle.
- Using existing code to perform common tasks: True—this is reuse.
- Programmer-defined functions can be value-returning or void: True in C/C++.
Common Pitfalls:
- Confusing a function's definition (written once) with its calls (used many times).
- Believing recursion or multiple calls require special permission—both are ordinary features.
Final Answer:
Functions can be called, or invoked, only once in a program
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