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Where do we use ## in C ?

Where do we use ## in C ?

Where do we use ## in C ?

Could any one help me as to how/where to use  the double #
symbol (##)in c?

RE: Where do we use ## in C ?

This is how it is explained in MS help.

Token-Pasting Operator

Operator    ##
Syntax     token##parameter

The token-pasting operator is used only with macros.

If ## precedes or follows a formal parameter in the definition of a macro, the actual argument is concatenated with the token on the other side of the ## when the macro is expanded. For example,

#define printvar(x) printf("%d", var##x)

causes the statement


to be expanded into



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