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1. Top results related to define statement in c

   • return statement in macro(#define) in C

     Top Answer

     Answered Sep 13, 2011 · 6 votes

     Simply do:

     #define sent_same_text(txt) (txt)-

     You only need return for functions. A macro is different in that it is a literal string insertion into your code. Make sure you have the parentheses around txt.

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     1/5

   • Define statement expected a declaration C++

     Top Answer

     Answered May 23, 2017 · 3 votes

     The problem is with the the #endif directive which is located inside the definition of the class (before the }; code), thus a second inclusion of this header file will only include the }; code causing the errors you got.

     BTW, instead of using the #ifndef pattern you can simply use #pragma once

     at the beginning of your file which has the same effect. You can read more about pragma once vs. using include guards in here.

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     2/5

   • Symbolic constants in C (#define statement)

     Top Answer

     Answered Oct 15, 2013 · 3 votes

     Regarding these defines, it doesn't, the expanded macros doesn't have a type. The pre-processor which processes the #define is just replacing text within the source code

     When you use these defines somewhere, e.g.

     int i = INTEGER_EXAMPLE;-

     This will expand to

     int i = 2;-

     Here the literal 2 (which in this context is an int) is assigned to an int.

     You could also do:

     char c = INTEGER_EXAMPLE;-

     Here too, the literal 2 is an int, and it is assigned to a char. 2 is within the limits of a char though, so all is ok.

     You could even do:

     int INTEGER_EXAMPLE = 2;-

     This would expand to

     int 2 = 2;-

     Which isn't valid C.

     Other Answers

     Answered Oct 15, 2013 · 10 votes

     #define-d names have no types. They just define textual replacements.

     What the compiler is seeing is the preprocessed form. If using GCC, try gcc -C -E somesource.c and have a look at the (preprocessed) output.

     In the 1980s the preprocessor was a separate program.

     Read about the cpp preprocessor, and preprocessor and C preprocessor wikipages.

     You could even define ill-defined names like

     #define BAD @*?$ some crap $?-

     And even more scary you can define things which are syntactically incomplete like

     #define BADTASTE 2 +-

     and later code BADTASTE 3

     Actually, you want to use parenthesis when defining macros. If you have

     #define BADPROD(x,y) x*y-

     then BADPROD(2+3,4+5) is expanded to 2+3*4+5 which the compiler understands like 2+ (3*4) +5; you really want

     #define BETTERPROD(x,y) ((x)*(y))-

     So that BETTERPROD(2+3,4+5) is expanded to ((2+3)*(4+5))

     Avoid side-effects in macro arguments, e.g. BETTERPROD(j++,j--)

     In general, use macros with care and have them stay simple.

     Other Answers

     Answered Oct 15, 2013 · 3 votes

     #define STRING VALUE

     is just an instruction for the pre-processor to replace the STRING with VALUE afterwards the compiler will take control and will check the types

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     3/5

   • #define usage in C/C++

     Top Answer

     Answered Jun 07, 2010 · 11 votes

     You want to use a Variadic macro.

     In your case, I believe you want:

     #define scanf(...) fscanf(inf,__VA_ARGS__)-

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     4/5

   • #define in C: what is happening

     Top Answer

     Answered Jun 20, 2020 · 4 votes

     calcCylinderArea(3.0,5.0+1)-

     (calcCircleArea(3.0)*5.0+1)-

     notice that it is not (5.0+1). Problem begins here.

     ((PI*(3.0)*(3.0))*5.0+1)-

     ((3.1*(3.0)*(3.0))*5.0+1)-

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     5/5

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2. www.geeksforgeeks.org › c-define-preprocessor#define in C - GeeksforGeeks

   www.geeksforgeeks.org › c-define-preprocessor

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   Jul 14, 2023 · Last Updated : 14 Jul, 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. The generics in C are also implemented using the #define ...

3. www.freecodecamp.org › news › constants-in-cConstants in C Explained – How to Use #define and the const ...

   www.freecodecamp.org › news › constants-in-c

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   Oct 26, 2021 · When you're programming, there are times when you'll want the values of certain variables to remain unchanged. In the C language, you'll likely define them as constants. You can define constants in C in a few different ways. In this tutorial, you'll learn how to use #define and the const.

4. learn.microsoft.com › en-us › cpp#define directive (C/C++) | Microsoft Learn

   learn.microsoft.com › en-us › cpp

   • Cached

   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. Syntax. #define identifier token-string opt #define identifier (identifier opt,...

5. www.cprogramming.com › preprocessor › define#define - C and C++ Syntax Reference - Cprogramming.com

   www.cprogramming.com › preprocessor › define

   • Cached

   #define The #define directive takes two forms: defining a constant and creating a macro. Defining a constant #define token [value] When defining a constant, you may optionally elect not to provide a value for that constant. In this case, the token will be replaced with blank text, but will be "defined" for the purposes of #ifdef and ifndef. If ...

6. stackoverflow.com › questions › 2806347c preprocessor - What is the purpose of the #define directive ...

   stackoverflow.com › questions › 2806347

   • Cached

   May 10, 2010 · 8 Answers. Sorted by: 15. #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: Simple Macros - basically just text replacement. Compile time constants are a good example: #define SOME_CONSTANT 12.

   Usage example

   #define SQUARE(x) ((x) * (x))

   See more on stackoverflow

7. codeforwin.org › c-programming › c-preprocessorC preprocessor directives - #include, #define, #undef and ...

   codeforwin.org › c-programming › c-preprocessor

   • Cached

   Nov 18, 2018 · #define preprocessor directive is the most useful preprocessor directive in C language. We use it to define a name for particular value/constant/expression. C preprocessor processes the defined name and replace each occurrence of a particular string/defined name (macro name) with a given value (micro body). Syntax to define a MACRO using #define

8. People also ask

   What is 'define' in C & C++?

   • #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: Simple Macros - basically just text replacement. Compile time constants are a good example: simply replaces the text SOME_CONSTANT with 12 wherever it appears in your code.

   What is the purpose of the #define directive in C++?

   stackoverflow.com/questions/2806347/what-is-the-purpose-of-the-define-directive-in-c

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   How to define constants in C?

   • Let's get started. One of the common ways to define constants in C is to use the #define preprocessor directive, as shown below: In the above syntax: is a placeholder for the name of the constant. It's recommended that you name constants in the uppercase, as it helps differentiate them from other variables defined in the program.

   Constants in C Explained – How to Use #define and the const Qualifier

   www.freecodecamp.org/news/constants-in-c-explained-how-to-use-define-and-const-keyword/

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   What does define do in C++?

   • In C++, #define has very narrow, specialized roles: Interacting with the standard libraries. For instance, #defining WINDOWS_LEAN_AND_MEAN before including windows.h turns off certain often-problematic macros like MAX. Advanced macros involving stringization (ie, macros that print debugging messages) or token-pasting.

   What is the purpose of the #define directive in C++?

   stackoverflow.com/questions/2806347/what-is-the-purpose-of-the-define-directive-in-c

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   What is the difference between value> and define> in C?

   • VALUE> is a placeholder for the value that takes. #define is a preprocessor directive. Before the compilation of the program, the preprocessor replaces all occurrences of with . In C, the preprocessors process the source code ahead of compilation to produce the expanded source code. This is illustrated below.

   Constants in C Explained – How to Use #define and the const Qualifier

   www.freecodecamp.org/news/constants-in-c-explained-how-to-use-define-and-const-keyword/

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9. www.programiz.com › c-programming › c-preprocessorC Preprocessor and Macros - Programiz

   www.programiz.com › c-programming › c-preprocessor

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   Example 1: #define preprocessor. #include <stdio.h> #define PI 3.1415 int main() { float radius, area; printf("Enter the radius: "); scanf("%f", &radius); // Notice, the use of PI . area = PI*radius*radius; printf("Area=%.2f",area); return 0; } Function like Macros. You can also define macros that work in a similar way as a function call.