CODEWITHSUNDEEP
c++
trustyhardware
trustyhardware

Reputation: 25

Parse Comma Delimited File without using <string>

I have a file which looks like:

123,Cheese,Butter
78,Milk,Vegetable,Fish

and I wish to read each line into a data type List which has int num and char things[3][10] using overloaded operator >>. So far I have:

friend istream& operator>> (istream &is, List &rhs)
{
  char comma;
  is >> rhs.num >> comma >> ... (I don't know how to continue)

  return is;
} // operator>>

Am I doing it right using char comma to skip a comma? How do I read different entries with different lengths separated by comma without using string?

Upvotes: 1

Views: 93

Answers (1)

W.F.
W.F.

Reputation: 13988

It will be only a pseudocode but if you really need to avoid std::string your best choice is to make it more or less look like this:

istream &operator >>(istream &s, YourType &mylist) {
   char mybuf[256];
   s.read(mybuf, 256);
   char *beg = mybuf;
   char *cur = beg;
   while (cur != mybuf + 256 && *cur!=0) {
      if (*cur == '\n') {
         mylist.addnext();
      }
      if (*cur == ',') {
         *cur = 0; //to make the char string end on each comma
         mylist.current.add(beg);
         beg = cur + 1;
      }
   }
}

Remember that if YourType will be for example vector<vector<const char *>> you will need to add the operator >> into the std namespace.

Upvotes: 1

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