A preprocessor directive is a message from programmer to the preprocessor.
Answer: A
Correct answer: True
A directive such as #include or #define is an instruction to the preprocessor - the phase that rewrites the source text before the compiler sees it. It is not part of the C language proper, which is why it has its own syntax and ends at the end of a line rather than at a semicolon.
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Macro calls and function calls work exactly similarly.
Answer: B
False, A macro just replaces each occurrence with the code assigned to it. e.g. SQUARE(3) with ((3)*(3)) in the program.
A function is compiled once and can be called from anywhere that has visibility to the funciton.
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A macro must always be defined in capital letters.
Answer: B
Correct answer: False
Capitals are a convention, not a requirement. They serve as a warning to the reader that the name will be substituted textually, with all the traps that carries. The preprocessor accepts any valid identifier, and the standard library itself defines lower-case macros such as getchar.
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Macros have a local scope.
Answer: B
Correct answer: False
A macro has no scope in the C sense at all. Its definition runs from the #define to the end of the file, or to a matching #undef - braces and functions mean nothing to the preprocessor, which works on text. A #define written inside a function is still in force after that function ends.
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Every C program will contain at least one preprocessor directive.
Answer: B
Correct answer: False
Nothing compels a program to use a directive. A program that neither includes a header nor defines a macro - int main(void) { return 0; } - is perfectly valid C. In practice almost every program includes something, but that is habit rather than a rule.
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Preprocessor directive #ifdef .. #else ... #endif is used for conditional compilation.
Answer: A
Correct answer: True
#ifdef / #else / #endif is exactly the mechanism for conditional compilation: only one branch survives preprocessing, and the other never reaches the compiler at all. It is the usual way of adapting a source file to different platforms or of compiling out debugging code.
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Macros with arguments are allowed
Answer: A
Correct answer: True
Function-like macros with parameters are ordinary: #define MAX(a,b) ((a) > (b) ? (a) : (b)). The arguments are substituted as text, which is why the parameters and the whole body need parenthesising and why an argument with a side effect can be evaluated more than once.
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In a macro call the control is passed to the macro.
Answer: B
Correct answer: False
There is no transfer of control. A macro is expanded in place, before compilation, so its body ends up written out at each call site - no jump, no stack frame, no return. That is the essential difference from a function: the speed of inline code, at the cost of size and of type checking.
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A header file contains macros, structure declaration and function prototypes.
Answer: A
Correct answer: True
A header typically carries exactly those three things - macros, type and structure declarations, and function prototypes - because they are what several source files need to share. What it should not carry is a definition that allocates storage or a function body, since including it in two files would then produce two definitions.
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The preprocessor can trap simple errors like missing declarations, nested comments or mismatch of braces.
Answer: B
Correct answer: False
The preprocessor does not parse C at all. It handles directives, expands macros and strips comments; it has no notion of declarations or of matching braces, so those errors surface later, in the compiler. It does report its own faults, such as a missing include file or an unclosed #if.
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