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Jul 14, 2023 · In C programming, #define is a preprocessor directive that is used to define macros. The macros are the identifiers defined by #define which are replaced by their value before compilation. We can define constants and functions like macros using #define.
May 14, 2024 · In C++, #define is a preprocessor directive used to define a macro. Macros are a way to represent a fragment of code or a constant value by giving it a name. When the preprocessor encounters the macro name in the code, it replaces it with the corresponding code fragment or value that is defined using the #define preprocessor.
Oct 11, 2024 · In C, a macro is a piece of code in a program that is replaced by the value of the macro. Macro is defined by #define directive. Whenever a macro name is encountered by the compiler, it replaces the name with the definition of the macro. Macro definitions need not be terminated by a semi-colon (;).
This C tutorial explains how to use the #define preprocessor directive in the C language. In the C Programming Language, the #define directive allows the definition of macros within your source code.
The C preprocessor is a macro preprocessor (allows you to define macros) that transforms your program before it is compiled. In this tutorial, you will be introduced to c preprocessors, and you will learn to use #include, #define and conditional compilation with the help of examples.
Nov 27, 2015 · #define is used to create macros in C and in C++. You can read more about it in the C preprocessor documentation . The quick answer is that it does a few things:
C #define. The C programming language's #define preprocessor directive provides a strong and flexible tool for declaring constants and producing macros. It conducts textual replacement before actual compilation during the pre-processing phase of C programs, where it plays a significant role.
#ifdef USE_CONST #define MYCONST const #else #define MYCONST #endif Then you can write code like this: MYCONST int x = 1; MYCONST char* foo = "bar"; and if you compile with USE_CONST defined (e.g. typically something -DUSE_CONST in the makefile or compiler options) then it will use the consts, otherwise it won't.
Aug 2, 2021 · The #define creates a macro, which is the association of an identifier or parameterized identifier with a token string. After the macro is defined, the compiler can substitute the token string for each occurrence of the identifier in the source file.
To define a multiline macro, each line before the last should end with a \, which will result in a line continuation. Related. C preprocessor tutorial. Popular pages. #define is used to define macros in C and C++.
