M4444 / TM

A Windows terminal based Turing machine simulator written in C.

TM

TM was created in 2014. as a project for a course in discrete mathematics. It's a C implementation of a Turing machine with the visuals and animation done in the same way as in Zmija.

Menu - tape input

[see the first menu]

The first menu presents options for inputting the tape:

1 through the console

2 through a text file

3 prints the input format

[see output]

'b' is used as the blank symbol, spaces and new lines are ignored

0 quit the application

Menu - program input

[see the second menu]

After the tape has been entered the second menu prompts you to chose the program input method:

1 through a text file

[Example program]

A program that checks if a binary number is divisible by 4:

f(q0,1)->(q1,1,+1)

f(q1,0)->(q1,0,+1)
f(q1,1)->(q1,1,+1)
f(q1,b)->(q2,b,-1)

f(q2,0)->(q3,0,-1)
f(q2,1)->(q-,1,+1)
f(q3,0)->(q+,0,+1)
f(q3,1)->(q-,1,+1)

2 chose an existing program

[see output]

Option 5 expects a binary number but all the other options expect unary numbers where zero is represented as '1', one as '11', two as '111' and so on. Options 3 and 4 expect two numbers separated by '0'.

• 1 zero function
• 2 successor
• 3 first projection
• 4 sum
• 5 divisibility by 4
• 0 quit the application

3 prints the input format

[see output]

• spaces and new lines are ignored
• f(q_i,a_i) -> (q_j,a_j,r)
  • q - internal state
  • a - tape alphabet symbol
  • r - head shift direction (+1 or -1)
  • i = {0, 1, ..., n}
  • j = {0, 1, ..., n, +, -}

0 quit the application

Controls

[see the controls]

Once both the tape and the program have been entered the Turing machine will be displayed. The step counter and current state are displayed in the bottom right corner.

v and b can be used to move the view of the tape. k runs one step of the Turing machine while and s and z start and stop a automatic run. Esc quits the application.

How it looks:

Prove that C is Turing complete: ☑️