Help understanding the code

Hi Guys hel please.. I'm new to open gl programming ...Can any body please help me or at least give me idea on what subdivideCircle, normalize, and drawtriangle functions is trying to do? Thanks ina advance!

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  // subdivide a triangle recursively, and draw them
    private void subdivideCircle(int radius, float[] v1, float[] v2, int depth)
    {
        float v11[] = new float[3];
        float v22[] = new float[3];
        float v00[] = {0, 0, 0};
        float v12[] = new float[3];
        if (depth==0)
        {
            //5. specify a color related to triangle location
            gl.glColor3f(v1[0]*v1[0], v1[1]*v1[1], v1[2]*v1[2]);
            for (int i = 0; i<3; i++)
            {
                v11[i] = v1[i]*radius;
                v22[i] = v2[i]*radius;
            }
            drawtriangle(v11, v22, v00);
            return;
        }
        v12[0] = v1[0]+v2[0];
        v12[1] = v1[1]+v2[1];
        v12[2] = v1[2]+v2[2];
        normalize(v12);
        // subdivide a triangle recursively, and draw them
        subdivideCircle(radius, v1, v12, depth-1);
        subdivideCircle(radius, v12, v2, depth-1);
    }

    // draw a circle with center at the origin in xy plane
    public void drawCircle(int cRadius, int depth)
    {
        subdivideCircle(cRadius, cVdata[0], cVdata[1], depth);
        subdivideCircle(cRadius, cVdata[1], cVdata[2], depth);
        subdivideCircle(cRadius, cVdata[2], cVdata[3], depth);
        subdivideCircle(cRadius, cVdata[3], cVdata[0], depth);
    }

    // normalize a 3D vector
    public void normalize(float vector[])
    {
        float d = (float)Math.sqrt(vector[0]*vector[0]
        +vector[1]*vector[1] + vector[2]*vector[2]);
        if (d==0)
        {
            System.out.println("0 length vector: normalize().");
            return;
        }
        vector[0] /= d;
        vector[1] /= d;
        vector[2] /= d;
    }

    public void drawtriangle(float[] v1, float[] v2, float[] v3)
    {
        gl.glBegin(GL.GL_TRIANGLES);
        gl.glVertex3fv(v1);
        gl.glVertex3fv(v2);
        gl.glVertex3fv(v3);
        gl.glEnd();
    }