Predefined macros - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is a predefined macro in C?

A predefined macro is a special identifier that the C compiler automatically defines before compilation. It provides useful information like the current file name, line number, or compilation date.

beginner

What does the predefined macro __FILE__ represent?

The __FILE__ macro expands to the name of the current source file as a string literal.

beginner

What value does the predefined macro __LINE__ hold?

The __LINE__ macro expands to the current line number in the source file as an integer constant.

intermediate

What information does the predefined macro __DATE__ provide?

The __DATE__ macro expands to a string literal representing the date when the source file was compiled, in the format "Mmm dd yyyy".

intermediate

How can predefined macros help in debugging C programs?

Predefined macros like __FILE__ and __LINE__ can be used to print the current file name and line number, helping programmers quickly find where an error or message originated.

Which predefined macro gives the current line number in a C source file?

A __TIME__

B __FILE__

C __DATE__

D __LINE__

The macro __LINE__ expands to the current line number in the source file.

What does the predefined macro __FILE__ return?

A The current line number

B The name of the current source file

C The compilation date

D The compilation time

The macro __FILE__ expands to the name of the current source file as a string.

Which predefined macro provides the date when the program was compiled?

A __DATE__

B __TIME__

C __FILE__

D __LINE__

The macro __DATE__ expands to the compilation date as a string.

How can predefined macros be useful in debugging?

A They can print the current file and line number

B They can optimize code speed

C They can change program logic

D They can store variable values

Predefined macros like __FILE__ and __LINE__ help identify where in the code an error or message occurs.

Which of these is NOT a standard predefined macro in C?

A __TIME__

B __DATE__

C __COMPILER__

D __FILE__

__COMPILER__ is not a standard predefined macro in C.

Explain what predefined macros are in C and list at least three common examples with their purpose.

Think about what information the compiler automatically provides during compilation.

Describe how you can use predefined macros to help find bugs in your C program.

Consider how knowing the exact file and line number can speed up fixing problems.