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Preprocessor Macro Definition

I am relatively new to C ++ and I am in the class. A lab was assigned to our class, and my teacher said the lab entry was a little hard to understand; however, he did not make any changes to the laboratory entry. So, I came across this part of the lab:

Preprocessor Macro Definition

The long-term convention uses macros, and this macro name must be TRACE_FUNC. A macro has a single parameter, a character, which will be replaced by the name of the function when the macro is applied to the code. The beginning of the macro is as follows:

#define TRACE_FUNC( symbol )  replacement-text`

and the preprocessor will replace the replacement text wherever there is a TRACE_FUNC (sym) line in the source code, and feed the character into this replacement.

NOTE. The #define statement must be on the same logical line. To keep the length manageable, you can avoid the newline character with a backslash at the end of the line; which will keep the preprocessor happy, allowing you to define the definition over multiple lines.

For this exercise, the replacement text should be complete, including the ending half-line.

Replaceable text should be an output statement that prints a character followed by a call to text (). and a new line for standard output. You can copy and modify one of the output statements from the warning.cpp source file.

warning.cpp- this is only the file we use and TRACE_FUNCis placed in the header file.

, , 100%, . , , , TRACE_FUNC. -, TRACE_FUNC. , , TRACE_FUNC, , , . , . , , , , , TRACE_FUNC.

, , , , TRACE_FUNC . , , foo() , foo() ( foo, ) . , , -, , # . , . ?

, , , .

#define TRACE_FUNC( foo() ) #foo() called. ;

#define TRACE_FUNC( foo ) #foo () called. ;

, , , #define. , , , .

, . TRACE_FUNC , , - , ? TRACE_FUNC, , ?

+5
2

, ! ++ , .

, , .

#define TRACE_FUNC(sym) std::cout << #sym << "() called\n"

void foo()
{
  TRACE_FUNC(foo);
  ...
}

, warning.cpp, std::cout, , , warning.cpp.

, TRACE_FUNC, . , , . , , .

, , , , . , , . , , .

+6

: libray printf

 #define TRACE_FUNC(sym) printf("%s() called", #sym);


TRACE_FUNC(printf)


printf() called

- . printf #define.

-1

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