What is preprocessor directive expected?
The preprocessor directives give instruction to the compiler to preprocess the information before actual compilation starts.
What is mean by preprocessor directive symbol?
Preprocessor directives are lines of the source file where the first non-whitespace character is # , which distinguishes them from other lines of text. The effect of each preprocessor directive is a change to the text and the result is a transformation of the text that does not contain the directives nor comments.
What is the use of conditional preprocessor directive in C#?
The Preprocessors used in C# are given below:
| Preprocessor | Description |
|---|---|
| #endif | Ends the conditional directive which began with #if |
| #else | If the symbolic value of #if evaluates to false the #else directive statements are executed |
| #elif | Creates a compound conditional directive which is executed if the symbolic value is true |
What is an example of preprocessor directives?
Examples of some preprocessor directives are: #include, #define, #ifndef etc. Remember that the # symbol only provides a path to the preprocessor, and a command such as include is processed by the preprocessor program. For example, #include will include extra code in your program.
What is #if and #endif in C#?
From Microsoft Docs: When the C# compiler encounters an #if directive, followed eventually by an #endif directive, it compiles the code between the directives only if the specified symbol is defined. The #if statement in C# is Boolean and only tests whether the symbol has been defined or not.
What is Ifndef in C?
The #ifndef directive checks whether a macro is not defined. If the identifier specified is not defined as a macro, the lines of code immediately follow the condition are passed on to the compiler.
What are the types of preprocessor directives?
There are 4 Main Types of Preprocessor Directives:
- Macros.
- File Inclusion.
- Conditional Compilation.
- Other directives.
How many types of preprocessor directives are there in C?
There are 4 Main Types of Preprocessor Directives: Macros. File Inclusion. Conditional Compilation. Other directives.
What is Ifndef and endif?
#ifndef checks whether the given token has been #defined earlier in the file or in an included file; if not, it includes the code between it and the closing #else or, if no #else is present, #endif statement.
Why do we need Ifndef?
#ifndef and #define are known as header guards. Their primary purpose is to prevent C++ header files from being included multiple times.
What is preprocessor explain 3 types of preprocessor?
What are the types of preprocessor directive?
Types of Preprocessor Directives
- # define.
- # include.
- # ifdef.
- # undef.
- #ifndef.
- # if.
- #else.
- #elif.
What is endif in C++?
In the C Programming Language, the #endif directive is used to define the following directives: #if, #ifdef , and #ifndef . Whenever the #endif directive is encountered in a program, it determines if the preprocessing of #if, #ifdef, or #ifndef has been completed successfully.
What are the four preprocessor directives for conditional compilation?
You use four preprocessor directives to control conditional compilation: #if: Opens a conditional compilation, where code is compiled only if the specified symbol is defined. #elif: Closes the preceding conditional compilation and opens a new conditional compilation based on if the specified symbol is defined.
Is the pound symbol a valid preprocessor directive?
Preprocessor directive expected A line began with the pound symbol (#), but the subsequent string was not a valid preprocessor directive. The following sample generates CS1024:
Can I use preprocessor directives to create macros?
Unlike C and C++ directives, you can’t use these directives to create macros. A preprocessor directive must be the only instruction on a line. The #nullable preprocessor directive sets the nullable annotation context and nullable warning context.
How do I use the Nullable preprocessor directive?
The #nullable preprocessor directive sets the nullable annotation context and nullable warning context. This directive controls whether nullable annotations have effect, and whether nullability warnings are given. Each context is either disabled or enabled. Both contexts can be specified at the project level (outside of C# source code).