Shortest Code to randomly place points and connect them

Java : 318 282 265

Because, ya know, Java:

class M{public static void main(String[]a){new Frame(){public void paint(Graphics g){int i=0,j,d=640,n=25,x[]=new int[n],y[]=x.clone();for(setSize(d,d);i<n;i++)for(j=0,x[i]=(int)(random()*d),y[i]=(int)(random()*d);j<i;g.drawLine(x[i],y[i],x[j],y[j++]));}}.show();}}

Its just a simple loop that makes random dots and draws lines between the current dot and all previous ones.

Example with 25 dots:

With line breaks and imports:

import java.awt.*;
import static java.lang.Math.*;

class M{
    public static void main(String[]a){
        new Frame(){
            public void paint(Graphics g){
                int i=0,j,d=640,n=25,x[]=new int[n],y[]=x.clone();
                for(setSize(d,d);i<n;i++)
                    for(j=0,x[i]=(int)(random()*d),y[i]=(int)(random()*d);
                        j<i;
                        g.drawLine(x[i],y[i],x[j],y[j++]));
            }
        }.show();
    }
}

Edit: Since we're not counting imports, I imported a couple more things to save some characters later.

Edit 2: OP added an allowance for hardcoding number of dots. -17 chars :)

Matlab (22)

gplot(ones(n),rand(n))

It is assumend that n is the number of points, and it looks like this for n=10:

n=6:

Explaination

gplot is a command for plotting graphs. The first argument is a n x n incidence matrix (full of ones, obviously). The second argument should be a n x 2 matrix with the coordinates of the points, but it does not matter if the second dimension is bigger that 2, so I just generate an n x n matrix of random values (which is 2 characters shorter than generating an n x 2 matrix).

Links to documentation

• gplot
• ones
• rand

Python 2 - 41 35

After importing some libraries as allowed for this challenge

from pylab import rand as r
from pylab import plot as p
from itertools import product as x
from itertools import chain as c

we can plot some number of connected points with just one line of code:

X=r(5,2);p(*zip(*c(*list(x(X,X)))))

(The screenshot was generated with 10 points.)