c++ question. (__)

Hi, everyone. I got a lot of help from the last question and I have another question.

If you look at the c++ code, there's a code that says #if and it's 1, 0, what's the role?

And when is #endif used?

#if #elif #endif

If it's declared like this, do I have to go through if or elif and end if at the end?

c++

2022-09-22 21:50

1 Answers

The syntax that starts with # in C/C++ is a macro classification processed by the preprocessor. Among them, the #if statement is paired with #endif as a conditional statement.

#if is the start of the branch statement, and #endif is the end of the if.

#if [Macro-modification]
#endif

If you want to write the else syntax, write #else between #if and #endif.

#if [Macro-modification]
// If 'Macro Formula' is true when compiling, compile with this part.
#else 
// If 'Macro Formula' is false when compiling, compile including this part.
#endif

If you want to branch with multiple conditions, you can use #elif to:

#if [Macro Formula 1]
#elif [Macro's formula 2]
#elif [Macro's formula 3]
#elif [Macro-modified...]]
#else
#endif

2022-09-22 21:50

If you have any answers or tips

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