Short Function.

Here's my implementation of function according to The Power of 10;

"Restrict functions to a single printed page."

As bonus, I didn't use global variable if possible. So if a function or procedure need a variable from others, it have to be passed using parameter on that function.

If we look at the code below, we know that it can be rewritten using a long single procedure or function. But according The Power of Ten, a function should be as short as possible so it could be printed in a single page.

So, instead one long multiple page function, I write/break it as several short-single-printed-page functions. :)

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
  TForm1 = class(TForm)
    Edit1: TEdit;
    Edit2: TEdit;
    Button1: TButton;
    Edit3: TEdit;
    Edit4: TEdit;
    procedure proses;
    function konversi(a:real;c,d:char):string;
    function konversiC(a:real;d:char):string;
    function konversiF(a:real;d:char):string;
    function konversiR(a:real;d:char):string;
    function konversiK(a:real;d:char):string;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
begin
  proses;
end;

procedure tform1.proses;
var
  a:real;
  s,b:string;
  c,d:char;
begin
  a:=strToFloat(edit1.Text);
  s:=edit2.Text;
  c:=s[1];
  s:=edit4.Text;
  d:=s[1];
  b:=konversi(a,c,d);
  edit3.Text:=b;
end;

function tform1.konversi(a:real;c,d:char):string;
begin
  case c of
    'C':konversi:=konversiC(a,d);
    'F':konversi:=konversiF(a,d)
    'R':konversi:=konversiR(a,d)
    'K':konversi:=konversiK(a,d)
    else konversi:='error';
  end;
end;

function tform1.konversiC(a:real;d:char):string;
begin
  case d of
    'C':konversiC:=floatToStr(a);
    'F':konversiC:=floatToStr(a*9/5+32);
    'R':konversiC:=floatToStr(a*4/5);
    'K':konversiC:=floatToStr(a+273);
    else konversiC:='Error';
  end;
end;

function tform1.konversiF(a:real;d:char):string;
begin
  case d of
    'C':konversiF:=floatToStr((a-32)*5/9);
    'F':konversiF:=floatToStr(a);
    'R':konversiF:=floatToStr((a-32)*4/9);
    'K':konversiF:=floatToStr((a-32)*5/9+273);
    else konversiF:='Error';
  end;
end;

function tform1.konversiR(a:real;d:char):string;
begin
  case d of
    'C':konversiR:=floatToStr(a*5/4);
    'F':konversiR:=floatToStr(a*9/4+32);
    'R':konversiR:=floatToStr(a);
    'K':konversiR:=floatToStr(a*5/4+273);
    else konversiR:='Error';
  end;
end;

function tform1.konversiK(a:real;d:char):string;
begin
  case d of
    'C':konversiK:=floatToStr(a-273);
    'F':konversiK:=floatToStr((a-273)*9/5+32);
    'R':konversiK:=floatToStr((a-273)*4/5);
    'K':konversiK:=floatToStr(a);
    else konversiK:='Error';
  end;
end;

end.

.

Another Turtle in Circle

There's always another way to solve something.

So, I have another code for "Turtle in Circle" code, :)

In the script below, I use turtle position to determine if it's still inside circle or not. If it outside circle, instead of send it to zero position, I send it to random position inside circle.

import turtle
from random import uniform
import numpy as np

turtle.shape("turtle")
#turtle.speed(1)
x = 0
y = 0
rmax=40

for i in range (1,1000):
    a = uniform (-90,90) #angle
    turtle.left(a)
    d = uniform (-75,75) #distance
    x = turtle.xcor()+d*np.cos(a*np.pi/180)
    y = turtle.ycor()+d*np.sin(a*np.pi/180)
    r = np.sqrt(x*x+y*y)
    if r>rmax:
        turtle.setx(uniform(-rmax,rmax))
        turtle.sety(uniform(-rmax,rmax))
        x = 0
        y = 0
    else:
        turtle.forward(d)

turtle.exitonclick()



 

.

Turtle in Circle

I use previous code and improve it so the turtle could only move at certain circle area.

import turtle
from random import uniform
import numpy as np

turtle.shape("turtle")
#turtle.speed(1)
x = 0
y = 0

for i in range (1,1000):
    a = uniform (-90,90) #angle
    turtle.left(a)
    d = uniform (-75,75) #distance
    x += d*np.cos(np.pi*a/180)
    y += d*np.sin(np.pi*a/180)
    r = np.sqrt(x*x+y*y)
    if r>40:
        turtle.setx(0)
        turtle.sety(0)
        x = 0
        y = 0
    turtle.forward(d)

turtle.exitonclick()



 

.

Anti MainStream.

Saat booming sepatu roda, Alfa malah sibuk berlatih skateboard, :D .

Random Turtle Movement.

I use turtle module, the standard module, in Python.

The turtle movement has random direction (angle), and random distance (forward/backward).

import turtle
from random import uniform

turtle.shape("turtle")
turtle.speed(1)
for i in range (1,100):
    #random angle
    a = uniform (-90,90)
    turtle.left(a)
    #random move
    d = uniform (-100,100)
    turtle.forward(d)

turtle.exitonclick()



 

.

The Power of 10

Rules for Developing Safety-Critical Code:

Avoid complex flow constructs, such as goto and recursion.

All loops must have fixed bounds. This prevents runaway code.

Avoid heap memory allocation.

Restrict functions to a single printed page.

Use a minimum of two runtime assertions per function.

Restrict the scope of data to the smallest possible.

Check the return value of all non-void functions, or cast to void to indicate the return value is useless.

Use the preprocessor sparingly.

Limit pointer use to a single dereference, and do not use function pointers.

Compile with all possible warnings active; all warnings should then be addressed before release of the software.

https://en.m.wikipedia.org/wiki/The_Power_of_10:_Rules_for_Developing_Safety-Critical_Code

Prime Number on Python

We've done it using Delphi, how about Python? Easy, :)

for i in range (2,200):
    prime = True
    for j in range (2,i):
        if i%j==0: 
            prime=False
    if prime==True:
        print i

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