连接形状中所有点的算法

Question

I'm trying to figure out how to connect all points in a shape, with the amount of points being dynamic.

I'll use a square to demonstrate, there's four points:

a - top left, b - top right, c - bottom right, d - bottom left

So...

var connections = [
    new Connection(a, b),
    new Connection(a, c),
    new Connection(a, d),
    new Connection(b, c),
    new Connection(b, d),
    new Connection(c, d)
];

Connects all points in a square (or any four sided polygon), but I want to do this automatically by looping through an array of points (displayed as abcd here for simplicity's sake) so it will work for any polygon. I tried to work out a pattern and implement it in a couple of for-loops but that failed. I expect it's really simple...

Any help is appreciated, thanks.

Answer 1

Pseudocode:

for (var i=0; i<Shape.Count; i++) {
  for (var j=i+1; j<Shape.Count; j++) {
    List.Add(i,j);
  }
}

Answer 2

var Connection = function (a, b) {
    console.log('Connecting ' + a + ' and ' + b);
}

var points = ['a','b','c','d','e'];

(function traverse() {
    for (var i = 0; i < points.length - 1; i += 1) {
        new Connection(points[0], points[ i + 1 ]);
    }
    points = points.slice(1);
    if (points.length > 1) {
        traverse(points);
    }
}());

That will output:

Connecting a and b
Connecting a and c
Connecting a and d
Connecting a and e
Connecting b and c
Connecting b and d
Connecting b and e
Connecting c and d
Connecting c and e
Connecting d and e 

Demo: http://jsfiddle.net/1j5n5x55/