Macro arguments are scanned and expanded before the substitution in macro body unless they are convert to a string representation (using #) or concatenated with other tokens (using ##).
Xstr(oper) => Xstr(multiply) =>str(multiply)=>"multiply" // in Xstr(x) , x is a simple argument so it will expand fully str(oper) =>"oper" // in str(x) , x is converting to string so it will not get expanded check this link : http://gcc.gnu.org/onlinedocs/cpp/Argument-Prescan.html#Argument-Prescan On Sun, Oct 28, 2012 at 3:28 PM, rahul sharma <[email protected]>wrote: > And when char *opername=str(oper); > > then o/p is oper....why behaviour is diff. in 2 cases > > On Sun, Oct 28, 2012 at 2:53 PM, rahul sharma <[email protected]>wrote: > >> #include<stdio.h> >> #include str(x) #x >> #define Xstr(x) str(x) >> #define oper multiply >> >> >> int main() >> { >> char *opername=Xstr(oper); >> printf("%s",opername); >> } >> so firstly Xstr is expanded to str(oper) >> then str(oper) is expanded to #oper now i have read that >> >> If, however, a parameter name is preceded by a # in the replacement text, >> the >> combination will be expanded into a quoted string with the parameter >> replaced by the actual argument...and in this case actual is also oper so >> it becomes "oper"...so it should print oper .....i thnik i am mistaken >> anyhre...correct??? >> > > -- > You received this message because you are subscribed to the Google Groups > "Algorithm Geeks" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/algogeeks?hl=en. > -- Vikram Pradhan | B.Tech| Computer Science & Engineering | NIT Jalandhar | 9740186063 | -- You received this message because you are subscribed to the Google Groups "Algorithm Geeks" group. To post to this group, send email to [email protected]. To unsubscribe from this group, send email to [email protected]. For more options, visit this group at http://groups.google.com/group/algogeeks?hl=en.
