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Oct 30th, 2004

how can i find out some char from string?

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i just want to find out '?','/','\', ect, from a char array, can anyone help me to find out what's wrong with the code below?

thanks

the reture value is not always what i want?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

static int is_valid_function_name(char *function_name_string)
{

for( ; *function_name_string !=' \0 ' ; function_name_string++ )
{
if ( *(function_name_string) ==' ? ' )

/* (*(function_name_string) ==' / ')||
(*(function_name_string ==' \\ ' )||
(*(function_name_string) ==' : ' )||
(*(function_name_string) ==' * ' )||
(*(function_name_string) ==' < ' )||
(*(function_name_string) ==' > ')||
(*(function_name_string) ==' | ')||
(*(function_name_string) ==' " ') */

{
return 0;
break ;
}

}
return 1;
}

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see_moonlight

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since Oct 2004

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Oct 30th, 2004

Re: how can i find out some char from string?

I would try it this way:

C++ Syntax (Toggle Plain Text)
#include <iostream>
 
static int is_valid_function_name(const char *function_name_string){
   for( ; *function_name_string !='\0' ; function_name_string++ ){
      switch (function_name_string[0]) {
         case '?' :
         case '/' :
         case '\\' :
	 case ':' :
         case '*' :
         case '<' :
         case '>' :
         case '\"' :
           return 0;
         default:
           break;
      }
   }
   return 1;
}
int main() {
   const char * legal_string = "there are no special characters";
   const char * non_legal_string = "there are special < characters ?";
   std::cout << "\"" << legal_string;
   if ( is_valid_function_name( legal_string ) )
       std::cout << "\" is a valid function name" << std::endl;
   else
       std::cout << "\" is not a valid function name" << std::endl;
 
   std::cout << "\"" << non_legal_string;
   if ( is_valid_function_name( non_legal_string ) )
       std::cout << "\" is a valid function name" << std::endl;
   else
       std::cout << "\" is not a valid function name" << std::endl;
   return 0;
}
#include <iostream>

static int is_valid_function_name(const char *function_name_string){
   for( ; *function_name_string !='\0' ; function_name_string++ ){
      switch (function_name_string[0]) {
         case '?' :
         case '/' :
         case '\\' :
	 case ':' :
         case '*' :
         case '<' :
         case '>' :
         case '\"' :
           return 0;
         default:
           break;
      }
   }
   return 1;
}
int main() {
   const char * legal_string = "there are no special characters";
   const char * non_legal_string = "there are special < characters ?";
   std::cout << "\"" << legal_string;
   if ( is_valid_function_name( legal_string ) )
       std::cout << "\" is a valid function name" << std::endl;
   else
       std::cout << "\" is not a valid function name" << std::endl;

   std::cout << "\"" << non_legal_string;
   if ( is_valid_function_name( non_legal_string ) )
       std::cout << "\" is a valid function name" << std::endl;
   else
       std::cout << "\" is not a valid function name" << std::endl;
   return 0;
}

ZuK

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since Oct 2004

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Oct 30th, 2004

Re: how can i find out some char from string?

I much prefer this one:

C++ Syntax (Toggle Plain Text)
#include <cstring>
 
static int is_valid_function_name(const char *function_name_string){
   return std::strpbrk(function_name_string, "?/\\:*<>\"") == NULL;
}
#include <cstring>

static int is_valid_function_name(const char *function_name_string){
   return std::strpbrk(function_name_string, "?/\\:*<>\"") == NULL;
}

By the way, qualifiying a global name as static to give it internal linkage is a deprecated feature. If this was the original intent of the function--as opposed to a static member function declared as inline--then an unnamed namespace is the recommended option:

C++ Syntax (Toggle Plain Text)
namespace {
   int is_valid_function_name(const char *function_name_string){
      return std::strpbrk(function_name_string, "?/\\:*<>\"") == NULL;
   }
}
namespace {
   int is_valid_function_name(const char *function_name_string){
      return std::strpbrk(function_name_string, "?/\\:*<>\"") == NULL;
   }
}

Though, ZuK, it strikes me that the original code may have been C instead of C++. In that case you may have just confused the OP more. If it really was C++ then I wonder why the return value was not bool.

Narue

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Oct 31st, 2004

Re: how can i find out some char from string?

i want to know if a function name is standard c name or not, what can i do from this code? i.e. a function name can be A~z ,0~9 and _, but can not begin wih 0~9 ?

see_moonlight

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This thread is more than three months old

No one has posted to this discussion for at least three months. Please let old threads die and do not reply to them unless you feel you have something new and valuable to contribute that absolutely must be added to make the discussion complete. Otherwise, please start a new thread in this forum instead.

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