Functions Questions and Answers

Answer: A

Correct answer: True

A C function returns at most one value. Where more is needed the usual devices are to pass pointers for the extra results, or to return a structure containing them all.

Answer: A

Correct answer: True

Under the older rules an omitted return type defaulted to int - which is why so much old code writes main() rather than int main(). C99 removed the default, so a modern compiler will at least warn.

Answer: B

Correct answer: False

main can be called recursively in C - it is an ordinary function in that respect, and the standard permits it. (C++ forbids it.) So the statement that every function except main may recurse is false.

Answer: A

Correct answer: True

C passes everything by value, but passing a pointer by value gives the function the caller’s address and so the effect of call by reference. Both styles are therefore available, which is why arrays - whose names decay to pointers - behave as though passed by reference.

Answer: A

Correct answer: True

A function may contain as many return statements as its logic needs - typically one per branch - and each may return a different value. The first one reached ends the function.

Answer: A

Correct answer: True

Once two files are linked together they share a single global namespace, so two external functions with the same name collide and the linker reports a duplicate symbol. The way to avoid it is to declare a function static, which confines it to its own file.

Answer: B

Correct answer: No

A function may return any type it likes, floating point included - double sqrt(double) is the obvious example. The statement is false.

Answer: B

Correct answer: No

A function declared void returns nothing at all, and needs no return statement - reaching the closing brace ends it. Only a function with a non-void return type is obliged to return a value.

Answer: A

Correct answer: Yes

Two return statements one after the other make the second unreachable: the first ends the function. Compilers warn about unreachable code because it almost always means the author intended something else.

Answer: B

Correct answer: No

The standard sets no limit of twelve. It requires an implementation to support at least 127 parameters, and most allow far more - so the practical limit is the compiler’s, not the language’s. (A function needing many parameters is usually better given a structure.)