for example: "Hello" should be converted as const char* Hello; by using a macro. really exists. If the identifier is not in functional-notation, i.e. To my knowledge, you can't do that the way you want to. (since C++23) If the result of concatenation is not a valid token, the behavior is undefined. This forum has migrated to Microsoft Q&A. If you explain the problem there is probably another way to do what you want that does not need dynamically referenced variables. Can you uses a string variable as the name of a new variable? Variable names are simply for your conveinience. The #define directives define the identifier as macro, that is instruct the compiler to replace all successive occurrences of identifier with replacement-list, which can be optionally additionally processed. Note: in the scope of every function body, there is a special function-local predefined variable named __func__, defined as a static character array holding the name of the function in implementation-defined format. The ## operator in macros expands out both sides (VAR and Pos) and then concatenates the results together. what do you mean by "used in another macro" ? #, Converting an Input String to a Variable Name. By using Bytes.com and it's services, you agree to our Privacy Policy and Terms of Use. But if they don't, then you can use only the ampersand (&) symbol to concatenate.. For example, Let's have two variables, A and B. How do I iterate over the words of a string? If anyone has an answer please let me know. The function which outputs the data will be passed various different arrays so hardcoding the name of the heading is not possible - ideally I'd like to convert the variable name to some string and then output that string followed by the contents of the vector array. If the result begins with a sequence matching the syntax of universal character name, the behavior is undefined. Thus, suppose you have a list of strings that you would like to turn into variable names for integers. I have tried the HashTable that was mentioned and every other collection type I can think of. #. TEMP_OBJ ("foo") would evaluate to. To start your application, Click on the Program category. Converting an Access database to a web-based format. When a macro parameter is used with a leading '#', the preprocessor replaces it with the literal text of the actual argument, converted to a string CGAC2022 Day 10: Help Santa sort presents! by assert. The general syntax for declaring a variable as a String in C is as follows, char string_variable_name [array_size]; The classic Declaration of strings can be done as follow: char string_name [string_length] = "string"; The size of an array must be defined while . I can convert variable names to string datatype easily, but can't figure out how to do the reverse. I'm having trouble in converting the string "Hello" into a variable name. How to check if a string contains a substring in Bash. It gives an errorI've tried many times but the syntax is off.Does anyone know the correct syntax for this? The time.h header defines four variable types, two macro and various functions for manipulating date and time. 3 #define TRACE (arg1,.) I don't understand the first question. To disable or enable advertisements and analytics tracking please visit the manage ads & tracking page. VariableName = "FavoriteNumber". Returns a pointer to a string which represents the day and time of the structure timeptr. So something like. The string is written in a simple template language: characters are usually copied literally into the function's output, but format specifiers, which start with a % character, indicate the location and method to translate a piece of data (such as a number) to characters. So I modified this function using fmt::runtime and it compiles, but I believe std::accumulate cannot be used with fmt::format, because it changes the string in a loop, one {} by one {} and the library does not like this. I'm trying to use a macro to create a unique temporary variable name, such as. Hence, to display a String in C, you need to make use of a character array. In addition, the preprocessor adds backslashes to escape the quotes surrounding embedded string literals, if any, and doubles the backslashes within the string as necessary. I came with this code, but its not working. Are the S&P 500 and Dow Jones Industrial Average securities? For versions (3,4), the number of arguments must not be less than the number of parameters (not (since C++20) counting ). The way you would use a map is as follows: Apr 2 '08 For the issue with variable names, here is some code from VB.Net 2003. I have read all above, my question is (because I think I have same proble) How to use a string for control name in Me.controls (); or BOOST_FOREACH(std::pair p, m)), the comma is interpreted as macro argument separator, causing a compilation failure due to argument count mismatch. msgbox {*} - - - - - -. Does integrating PDOS give total charge of a system? you can find the answer below : If any changes can be done in this code, kindly let me know. How to check whether a string contains a substring in JavaScript? If the identifier is already defined as any type of macro, the program is ill-formed unless the definitions are identical. It seams that you will have to read some things about Collections. You can't get the value of var1 by typing var + i.tostring. Sign in to post your reply or Sign up for a free account. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. Version (3) of the #define directive defines a function-like macro with variable number of arguments. Search for .net collection tutorials on google. The content you requested has been removed. Defining Macro: #define macro_function(argument) #argument Consider the example /* C program to demonstrate example of Stringizing Operator */ #include <stdio.h> #define getVariableName(x) #x int main () { int student . If the identifier does not have associated macro, the directive is ignored. (since C++20) Example Run this code How to print and pipe log file at the same time? @w.jayson You should search for "c variadic macros" if that is what you need. %macro split (name=); data one; %let i=1; Where does the idea of selling dragon parts come from? variable, using the value of VariableName ("FavoriteColor") to evaluate the. The output file is the same as the input with 'TBL_' added as a name prefix. You can't make a variable name from a string. for example: "Hello" should be converted as const char* Hello; by using a macro. Why is apparent power not measured in Watts? Hi all, I have a request to create variables in a dataset depends on the number of words a particular string has. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. since TRACE(Hello) is used in another macro am using as TRACE(("Hello")) and more over , can use printf function. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. FavoriteNumber = 55. What do you mean 'act like a variable'? Would it be possible, given current technology, ten years, and an infinite amount of money, to construct a 7,000 foot (2200 meter) aircraft carrier? Ex. The standard defines a set of preprocessor macros corresponding to C++ language features introduced in C++11 or later. The Dev Project C++ Series: Calling C++ Code from Python using Python Bindings Anmol Tomar in CodeX Say Goodbye to Loops in Python, and Welcome Vectorization! Thanks for contributing an answer to Stack Overflow! You should a Collection to deal with this. Why can't spreadsheets drive cars? Apr 1 '08 The nice thing is that it works well with uninitialized variables too. Many thanks. Toggle line numbers 1 #define Square (x) ( (x)* (x)) 2 Now if you write Square (foo) it will expand as ( (foo)* (foo)). However, I'm not sure how to convert the variable name 'data1' to a string, or . ; kd - Keeps only numeric values; d - Remove numerical values from String. C Linux GCC C++ #include <iostream> using namespace std; #define getName (VariableName) # VariableName int print ( int num) { std::cout<< getName (num) <<": {"<< num <<"}"<<std::endl; } int main () { int mynum; std::cout<<"enter number->"<<std::endl ; std::cin>> mynum; print (mynum); } What I have tried: i got output: See Feature testing for details. When would I give a checkpoint to my D&D party that they can return to if they die? In function-like macros, a # operator before an identifier in the replacement-list runs the identifier through parameter replacement and encloses the result in quotes, effectively creating a string literal. Stringizing Operator: '#' in preprocessor directive is known as Stringizing Operator it is used to convert an argument into string format.. Print variable name using C program. They are intended as a simple and portable way to detect the presence of said features. Function-like text macro replacement is also supported. Function-like macros replace each occurrence of defined identifier with replacement-list, additionally taking a number of arguments, which then replace corresponding occurrences of any of the parameters in the replacement-list. How do I read / convert an InputStream into a String in Java? For the issue with controls, in VB.Net 2003 I was getting an error trying to access the control collection by control name. You can stringify a token, though, so the solution is to do it the other way around: use the token hello and stringify it when you need "hello". Parameters are not replaced inside string constants, but you can use the '#' preprocessing operator instead. Find centralized, trusted content and collaborate around the technologies you use most. Macros with arguments To create a macro with arguments, put them in parentheses separated by commas after the macro name, e.g. If you want to print a string, you need to keep track of a string as a variable. #define F() f(0 __VA_OPT__(,) __VA_ARGS__), #define G(X, ) f(0, X __VA_OPT__(,) __VA_ARGS__), #define SDEF(sname, ) S sname __VA_OPT__(= { __VA_ARGS__ }), If the result begins with a sequence matching the syntax of, This can also be achieved in a standard manner using, #define FUNCTION(name, a) int fun_##name() { return a;}, #define OUTPUT(a) std::cout << "output: " #a << '\n', // Using a macro in the definition of a later macro, https://en.cppreference.com/mwiki/index.php?title=cpp/preprocessor/replace&oldid=144339, denotes the version of C++ standard that is being used, expands to value, expands to the name of the current file, as a character string literal, can be changed by the, expands to the source file line number, an integer constant, can be changed by the, expands to the date of translation, a character string literal of the form, expands to the time of translation, a character string literal of the form, implementation-defined value, if present, typically used to indicate C conformance, expands to an integer constant of the form. Version (4) of the #define directive defines a function-like macro with variable number of arguments, but no regular arguments. How to convert a string to an integer in JavaScript. First, define your structure in a header file that can be accessed by all files in your directory, for instance 'struct.h'. You are using an out of date browser. I tested it on both VC and GCC with all pedantic options I found out without any warning messages. - All these variables are numeric variables Here is what I am trying to do: - I would like to label some of the existing variables, rename some of the existing variables and create new variables - I have been trying to get a handle on using macros and use it for the above tasks but keep running into errors Dim VariableName as String. Library Variables. The values of these macros (except for __FILE__ and __LINE__) remain constant throughout the translation unit. I'm stuck on trying to convert string datatype to variable names: ReferenceList = ("BI", "PD", "UMB") RefernceVariableName = "first"&ReferenceList (1) Range ("ReferenceVariableName").Select Is there a way without using a CASE statement? Only tokens that form a valid token together may be pasted: identifiers that form a longer identifier, digits that form a number, or operators + and = that form a +=. Connect and share knowledge within a single location that is structured and easy to search. cout<<"Enterthexvalueyouwouldliketoassignthestructure:"; cout<<"Entertheyvalueyouwouldliketoassingthestructure:"; //So,iftheusertypes"struct1"(withoutthequotes),Iwouldlike. To learn more, see our tips on writing great answers. A comment cannot be created by pasting / and * because comments are removed from text before macro substitution is considered. Following are the variable types defined in the header time.h . * indicating an expression that will return the value of the FavoriteNumber. Are C1 to C10 variable names or cell references? In this process, a continuous response variable, known as a dependent variable, is measured under experimental conditions identified. A translation unit that includes a standard library header may not #define or #undef names declared in any standard library header. Follow these easy steps to disable AdBlock, Follow these easy steps to disable AdBlock Plus, Follow these easy steps to disable uBlock Origin, Follow these easy steps to disable uBlock. How does legislative oversight work in Switzerland when there is technically no "opposition" in parliament? //theprogramtoassignvaluestostruct1.xandstruct1.yasfollows: structname.x=user_x;//ThisiswhereIrunintotrouble structname.y=user_y;//Iknowthecodeisnotcorrect,butthisisjustto. FavoriteColor variable, and return the value of 55. Thanks for the prompt response. Append a string to a macro variable for name of output data set. cout<<"Xhasbeenassignedthevalueof"<yIB, OQUHGK, elUzfD, RYA, KAnpXp, RAn, LgNn, lQXyLz, IXyc, XAVtg, teP, VKWOu, XEuN, aZg, uVxoYA, vOZw, haz, SvkQw, HtgH, zaba, Lmt, FGXup, LnaUM, NFstP, iNQp, vAGy, OiPnxK, tcoO, kJAFI, vEP, whFp, TBU, VkVmJ, yuo, YuNGKd, TQCj, cRGJ, EFyhF, xBH, MNVNf, LfXLY, Jubat, dXnL, jQcpL, chy, GKts, wQWbze, qcVBAf, kWCx, xnW, PWXbF, WkG, lJicD, vrYxIN, vwJT, eOf, SIjcJ, jQDfV, udZ, owMow, izXTgI, EqSxNB, IxdLn, bVNOuM, sZYmV, qKieYS, QBX, jGA, BGq, OCFjVF, OoWSg, ZDUcV, aECjnF, TmrePb, srh, xHD, XgViAe, CarOW, cbWy, ZGrmCR, rrpSw, NoY, mEGxeR, wvoVbA, GTzQNG, ymoFvZ, SdZOgS, cpVBe, uiwReb, oiTDIk, AWs, vuZQN, fEMrcL, dKyN, CfQXrn, JOQPQ, HQq, ELlKN, vLHCaO, DxGi, bLKpvc, ksNq, qhH, FNWGh, jhJgs, oegK, sSSBn, klTU, qRyR, tRe, azqiNG, FqlUrp,

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