Read/Write vectors of OpenCV Points.

parser.cpp

#include <vector>
#include <string>
#include <fstream>
#include <iostream>
#include <opencv2/opencv.hpp>

using namespace std;
using namespace cv;


void writePointVector(const vector<Point>& pts, const string& filename)
{
	ofstream fout(filename.c_str());
	if(fout.is_open())
	{
		fout << "[\n";
		for(int i=0; i<pts.size()-1; i++)
			fout << "\t{ \"x\": " << pts[i].x << ", \"y\": " << pts[i].y << " },\n";
		fout << "\t{ \"x\": " << pts[pts.size()-1].x << ", \"y\": " << pts[pts.size()-1].y << " }\n";
		fout << "]\n";
		fout.close();
	}
	else
		cout << "Unable to open " << filename << endl;
}

void readPointVector(const string& filename, vector<Point>& pts)
{
	ifstream fin(filename.c_str());
	string line;
	if(fin.is_open())
	{
		while(getline(fin, line))
		{
			char* token;
			token = strtok((char*)line.c_str(), " \t,[]{}:\"");
			while(token != NULL)
			{
		 		char *x=NULL, *y=NULL;
		 		if(*token == 'x')
		 		{
					x = strtok(NULL, " \t,[]{}:\"");
					strtok(NULL, " \t,[]{}:\"");
					y = strtok(NULL, " \t,[]{}:\"");
		 		}
		 		else if(*token == 'y')
		 		{
					y = strtok(NULL, " \t,[]{}:\"");
					strtok(NULL, " \t,[]{}:\"");
					x = strtok(NULL, " \t,[]{}:\"");
		 		}
		 		if(x!=NULL && y!=NULL)
		 			pts.push_back(Point(atoi(x), atoi(y)));
		 		token = strtok(NULL, " \t,[]{}:\"");
			}
		}
		fin.close();
	}
	else
		cout << "Unable to open " << filename << endl;
}

int main()
{
	vector<Point> pts;
	// pts.push_back(Point(2, 3));
	// pts.push_back(Point(7, 34));
	// pts.push_back(Point(89, 56));
	// pts.push_back(Point(-1, 7));
	// writePointVector(pts, "vector_output.txt");
	readPointVector("vector_input.txt", pts);
	for(int i=0; i<pts.size(); i++)
		cout << "x: " << pts[i].x << ", y: " << pts[i].y << endl;
	return 0;
}

terminal output for reading form vector_input.txt

x: 2, y: 3
x: 34, y: 7
x: 89, y: 56
x: 9, y: 1
x: -67, y: -9
x: 59, y: 2

vector_input.txt

[
	{ "x":	 2, "y": 3 },
	{ "y": 7, "x": 34 },
	{ "x": 89, "		y": 56 },
	{ "y":	1, "x": 9 },
	{ "y": -9, "x": -67 },
	{ "x  ":   59, "y": 2 }
	
]

vector_output.txt

[
	{ "x": 2, "y": 3 },
	{ "x": 7, "y": 34 },
	{ "x": 89, "y": 56 },
	{ "x": -1, "y": 7 }
]