Macro for concatenating two strings in C -


I am trying to define a macro that assumes 2 strings and a space between them Joins back together It seems that I can use any character which I want apart from space, for example: 

  #define conc (str1, str2) # str1 ## # str2 # Define space_conc (str1, str2) conc (str1, -) ## # straw2 space_ncc (iden, oop);

space_conc back "idan-oop"

Let me back "idan oop", some suggestions?

try it 

  #define space_conc (str1, str2) # Using the string '##', adding symbols is not done for strings, wires can be sequated simply in C, and the compiler will add them. , Which is what this macro does. First turns the strobe into strobe and straight 2 (if you use it like the  space_conc (hello, world) ) and they are used by each other Near sir This is inbetween in space, string, the resulting extension will be understood by such compiler. 
 
  "hello" "" "world"  
 
 
  Edit 
 
  ## The macro extension is used in this way, we say that you have 
 
  #dumb_macro (a, b) ##b  
 
 The result of  dumb_macro (hello, world)  
 
  helloworld  
 
 which is not string But there is a symbol and you will probably end up with an undefined symbol error saying 'helloworld' does not exist unless you define it before. It would be legal: 
 
  int helloworld; Dumb_macro (Hello, World) = 3; Printf ("helloworld =% d \ n", helloworld); // & lt; - will print 'helloworld = 3'

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