Re: std::vector : begin, end and insert - Using Objects instead of ints

On Wed, 11 Apr 2007 04:19:36 -0700, "Nobody" <Nobody@yahoo.com> wrote:


There are several overloads of std::vector<T>::insert method.

I think the simplest form is:

  // Insert a new point in 3rd position
  points.insert( points.begin() + 2, Point(100, 200) );

You might want to consider the code I pasted into this post (see
main() function).
The output is following:

<OUTPUT>
*** TEST VECTOR INSERT ***

Point list:
[(1, 3), (2, 0), (3, 10), (33, 312)]
After insertion:
[(1, 3), (2, 0), (100, 200), (3, 10), (33, 312)]

</OUTPUT>

<CODE>

//
// Testing std::vector insert
// by MrAsm
//

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

// A 2D point
class Point
{
public:

    Point() : X(0), Y(0) {}
    Point( int x, int y ) : X(x), Y(y) {}

    int X;
    int Y;

    std::string ToString() const
    {
        std::ostringstream os;
        os << "(" << X << ", " << Y << ")";
        return os.str();
    }
};

typedef std::vector<Point> PointList;

// Print list of points
std::ostream & operator<<( std::ostream & os,
                           const PointList & points )
{
    if ( ! points.empty() )
    {
        os << "[" << points.at(0).ToString();
        for ( size_t i = 1; i < points.size(); i++ )
        {
            os << ", " << points.at(i).ToString();
        }
        os << "]";
    }
    else
    {
        os << "[<<empty>>]";
    }

    return os;
}

using std::cout;
using std::endl;

int main()
{
    cout << "*** TEST VECTOR INSERT ***" << endl;
    cout << endl;

    PointList points;
    points.push_back(Point(1, 3));
    points.push_back(Point(2, 0));
    points.push_back(Point(3, 10));
    points.push_back(Point(33, 312));

    cout << "Point list: " << endl;
    cout << points << endl;

    // Insert in 3rd position
    points.insert( points.begin() + 2, Point(100, 200) );
    cout << "After insertion:" << endl;
    cout << points << endl;

    system("PAUSE");
    return 0;
}

</CODE>

MrAsm