Please consider the code below. This is a smaller version of what I'm trying to accomplish.
Point instances will get random values to be printed in a 2D grid. In order not to have duplicates, I'm inserting them in positions.
ret pair is used by me in order to know whether a new element was inserted (ret.second == true) or not (ret.second == false).
The problem is that I get the message:
a.cpp:59:77: error: invalid operands of types 'bool' and '<unresolved overloaded function type>' to binary 'operator<<'
when try to compare ret.second with true or false.
What am I doing wrong?
#include <iostream>
using std::cout; using std::cerr; using std::endl; using std::cin;
#include <string>
using std::string;
#include <vector>
using std::vector;
#include <map>
using std::map;
#include <set>
using std::set;
#include <utility>
using std::pair; using std::make_pair;
#include <cmath>
#include <cstdlib>
class Point
{
public:
unsigned int x_pos;
unsigned int y_pos;
};
int main ()
{
std::vector<Point *> stream;
std::set<std::pair<unsigned int, unsigned int> > positions;
pair<set<pair<unsigned int, unsigned int> >::iterator, bool> ret;
Point * p = new Point;
p->x_pos = 3;
p->y_pos = 4;
stream.push_back(p);
p->x_pos = 1;
p->y_pos = 1;
stream.push_back(p);
unsigned int x_rand;
unsigned int y_rand;
unsigned int i (0); // Assign a position for every point in the stream not yet assigned to the 2D world.
for (vector<Point *>::iterator it = stream.begin(); it != stream.end(); ++it) {
cout << "iteration: " << i << endl;
ret.second = false;
while ( ret.second == false ) {
x_rand = rand() % 2;
y_rand = 0; // this would be another nr.
pair <unsigned int, unsigned int> p (x_rand, y_rand);
cout << " try to insert pair x,y = " << x_rand << "," << y_rand << endl;
ret = positions.insert (p);
if (ret.second == false) { cout << "element already present: " << endl; }
else { cout << " just inserted new element. " << ret.second==true << endl; } // ERROR IN THIS LINE.
}
++i;
}
}