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This program implements a nondeterministic Turing machine simulator in C.
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IN
OUT
Tests
MT.c
README.md

README.md

nondeterministic-turing-machine-simulator

This program implements a one tape nondeterministic Turing machine simulator in C, simulating the nondeterminism with a queue where are stored all the possible possibilities. Every cicle the last element of the queue will be analyzed and the program will act accordingly. The transitions are stored in a array (representing states) of arrays (representing chars), from each cell of the last array starts a list in which every element contains a transition (only the char to be written, the next state and the movement).

This program accept files written in the following way:

tr
0 a b 1 R
0 a c 1 R
1 a d 0 R
acc
0
max
50
run
a
aa
aaaaaaaaaa
aaaaaaa
aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa


'tr'--->following this statement there are all the transitions that describe the turing machine.
'acc'--->following this statement there are all the acceptance states.
'max'--->following this statement there is the maximum number of moves, this is done in order to prevent infinite loops.
'run'--->following this statement there are all the input strings, that will be executed one at a time.
The program will give one output for each input string. The output can be:
-'0': when the string cannot be accepted (does not belong to the language specified in the transitions);
-'1': when the string is accepted (does belong to the language specified in the transitions);
-'U': when the program exceeds the maximun number of moves, whether the string is to accept or to refuse.


Example:
taken the single instruction:
0 a b 1 L
-'0' means the starting state of this instruction;
-'a' is the (seen) character the machine sees whilst being in the starting state (0 in this example);
-'b' is the character supposed to be written after reading the seen character, replacing it in the same spot;
-'1' is the new state, and will be the starting state of another instruction (if not this state might be an accptance state);
-'L' means to which spot the machine would move, meaning the machine will read its content (R for right, S stop {it stays in the same spot});

This program example will accept all the strings even multiple of the string 'aa' and it will print strings multiple of 'bcd' and 'cbd' and their mixes,
because of his nondetermination.

IN folder contains examples of input files.

OUT folder contains outputs of the example inputs.

TM.c is the simulator C code.

Tests folder contains more tough versions of the IN folder files.

I've done this for school purpose.

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