Question

I have a text file, the contents are

Point1, [5, 6]
Line2, [1, 2, 3], [-5, 55, 33]
Point2, [5, 3, 1]
Line1, [1, 2], [5, 7]

I will do comparisions, like the first variable (Point1, Line2, Point2, Line1)

If it is point1, it will be stored into point 1 array, and 5 being set as x, and y being set as 6.

How do I set the delimter to commas and also the ‘[‘ and ‘]’. I just need the variable Point1, 5 and 6 to store them accordingly.

Answer 1

I would solve this problem the simplest way possible – read the file using getline and then replace all the occurances of ,, [ and ] with spaces. Then you can read all the input using std::istringstream from <sstream>. You could also use regular expressions(if you use boost or c++-11), but I believe what I suggest should do the job.

EDIT: here is an example how to do what I suggest. I will only show you how to input points, to handle lines as well you will have to add an if statement based on name.

#include <iostream>
#include <string>
#include <sstream>

using namespace std;

int main() {
  string line;

  while (getline(cin, line)) {
    for (unsigned i = 0; i < line.size(); ++i) {
      if (line[i] == '[' || line[i] == ']' || line[i] == ',') {
        line[i] = ' ';
      }
    }
    istringstream in(line);

    string name;
    double x,y;
    in >> name >> x >> y; // Point1 <x> <y>
    ... do something with the point...
  }

  return 0;
}

Also you can use replace_if from <algorithm> to replace the symbols, but I decided it will be easier for you to understand this solution.