Download code

From LiteratePrograms

Jump to: navigation, search

Back to Turing_machine_simulator_(C)

Download for Windows: zip

Download for UNIX: zip, tar.gz, tar.bz2

example_output.txt

 1 $ simulate_turing_machine ab
 2 v
 3 ab############################################################################
 4  v
 5 #b############################################################################
 6   v
 7 #b############################################################################
 8  v
 9 #b############################################################################
10 v
11 ##############################################################################
12  v
13 ##############################################################################
14   v
15 ##############################################################################
16    v
17 ##############################################################################
18


simulate_turing_machine.c

  1 /* Copyright (c) 2010 the authors listed at the following URL, and/or
  2 the authors of referenced articles or incorporated external code:
  3 http://en.literateprograms.org/Turing_machine_simulator_(C)?action=history&offset=20070614192605
  4 
  5 Permission is hereby granted, free of charge, to any person obtaining
  6 a copy of this software and associated documentation files (the
  7 "Software"), to deal in the Software without restriction, including
  8 without limitation the rights to use, copy, modify, merge, publish,
  9 distribute, sublicense, and/or sell copies of the Software, and to
 10 permit persons to whom the Software is furnished to do so, subject to
 11 the following conditions:
 12 
 13 The above copyright notice and this permission notice shall be
 14 included in all copies or substantial portions of the Software.
 15 
 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 23 
 24 Retrieved from: http://en.literateprograms.org/Turing_machine_simulator_(C)?oldid=10481
 25 */
 26 
 27 #include <stdlib.h>

 28 #include <stdio.h>

 29 #include <string.h>

 30 
 31 #include <ctype.h>

 32 
 33 #include "simulate_turing_machine.h"

 34 
 35 
 36 struct turing_machine_state {
 37     int control_state;
 38     int head_position;
 39     int tape_size;
 40     symbol* tape;
 41 };
 42  /* This structure need not be public */
 43 struct turing_machine_state
 44 create_initial_state(int initial_control_state, int input_string_length, symbol* input_string) {
 45     struct turing_machine_state state;
 46     state.control_state = initial_control_state;
 47     state.head_position = 0; /* Initially at left end */
 48     state.tape_size = input_string_length;
 49     state.tape = malloc(sizeof(symbol)*input_string_length);
 50     if (state.tape == NULL) {
 51         printf("Out of memory");
 52         exit(-1);
 53     }
 54 
 55     memmove(state.tape, input_string, sizeof(symbol)*input_string_length);
 56     return state;
 57 }
 58 
 59 void free_state(struct turing_machine_state* state) {
 60     free(state->tape);
 61 }
 62 
 63 void update_state(struct turing_machine_state* state, int new_control_state,
 64                   enum direction dir, char write_symbol, char blank_symbol)
 65 {
 66     state->control_state = new_control_state;
 67     state->tape[state->head_position] = write_symbol;
 68     if (dir == DIR_LEFT && state->head_position > 0) {
 69         state->head_position--;
 70     } else { /* dir == DIR_RIGHT */
 71         state->head_position++;
 72     }
 73     if (state->head_position >= state->tape_size) {
 74         int i, old_tape_size = state->tape_size;
 75         symbol* new_tape = realloc(state->tape, old_tape_size*2 + 10);
 76         if (new_tape == NULL) {
 77             printf("Out of memory");
 78             exit(-1);
 79         }
 80         state->tape = new_tape;
 81         state->tape_size *= 2;
 82         for (i=old_tape_size; i < state->tape_size; i++) {
 83             state->tape[i] = blank_symbol;
 84         }
 85     }
 86 
 87 }
 88 
 89 void trace_state(struct turing_machine_state* state, symbol blank_symbol) {
 90     int i;
 91     for(i=0; i < TRACE_TAPE_CHARS && i < state->head_position; i++) {
 92         printf(" ");
 93     }
 94     if (i < TRACE_TAPE_CHARS) {
 95         printf("v"); /* points down */
 96     }
 97     printf("\n");
 98     for(i=0; i < TRACE_TAPE_CHARS; i++) {
 99         printf("%c", i < state->tape_size ? state->tape[i] : blank_symbol);
100     }
101     printf("\n");
102 }
103 
104 
105 
106 int is_in_int_list(int value, int list_size, int list[]) {
107     int i;
108     for(i=0; i<list_size; i++) {
109         if (list[i] == value) {
110             return 1;
111         }
112     }
113     return 0;
114 }
115 
116 void simulate(struct turing_machine machine, int input_string_length, symbol* input_string) {
117     struct turing_machine_state state = 
118         create_initial_state(machine.initial_control_state, input_string_length, input_string);
119     trace_state(&state, machine.blank_symbol);
120 
121     while (!is_in_int_list(state.control_state, machine.num_accepting_states,
122                            machine.accepting_states)) {
123         struct transition_result next =
124             machine.transition_table[state.control_state]
125                                     [(int)state.tape[state.head_position]];
126         update_state(&state, next.control_state, next.dir,
127                      next.write_symbol, machine.blank_symbol);
128         trace_state(&state, machine.blank_symbol);
129 
130     }
131     free_state(&state);
132 }
133 
134


simulate_turing_machine.h

 1 /* Copyright (c) 2010 the authors listed at the following URL, and/or
 2 the authors of referenced articles or incorporated external code:
 3 http://en.literateprograms.org/Turing_machine_simulator_(C)?action=history&offset=20070614192605
 4 
 5 Permission is hereby granted, free of charge, to any person obtaining
 6 a copy of this software and associated documentation files (the
 7 "Software"), to deal in the Software without restriction, including
 8 without limitation the rights to use, copy, modify, merge, publish,
 9 distribute, sublicense, and/or sell copies of the Software, and to
10 permit persons to whom the Software is furnished to do so, subject to
11 the following conditions:
12 
13 The above copyright notice and this permission notice shall be
14 included in all copies or substantial portions of the Software.
15 
16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
23 
24 Retrieved from: http://en.literateprograms.org/Turing_machine_simulator_(C)?oldid=10481
25 */
26 
27 #ifndef _SIMULATE_TURING_MACHINE_H_

28 #define _SIMULATE_TURING_MACHINE_H_

29 
30 #define TAPE_ALPHABET_SIZE 256

31 
32 #define TRACE_TAPE_CHARS   78

33 
34 typedef char symbol;
35 
36 enum direction { DIR_LEFT, DIR_RIGHT };
37 
38 struct transition_result {
39     int control_state;
40     symbol write_symbol;
41     enum direction dir;
42 };
43 
44 struct turing_machine {
45     int initial_control_state;
46     char blank_symbol;
47     int num_accepting_states;
48     int* accepting_states;    
49     struct transition_result** transition_table;
50 };
51 
52 void simulate(struct turing_machine machine, int input_string_length, symbol* input_string);
53 
54 
55 #endif /* #ifndef _SIMULATE_TURING_MACHINE_H_ */

56


test_driver.c

  1 /* Copyright (c) 2010 the authors listed at the following URL, and/or
  2 the authors of referenced articles or incorporated external code:
  3 http://en.literateprograms.org/Turing_machine_simulator_(C)?action=history&offset=20070614192605
  4 
  5 Permission is hereby granted, free of charge, to any person obtaining
  6 a copy of this software and associated documentation files (the
  7 "Software"), to deal in the Software without restriction, including
  8 without limitation the rights to use, copy, modify, merge, publish,
  9 distribute, sublicense, and/or sell copies of the Software, and to
 10 permit persons to whom the Software is furnished to do so, subject to
 11 the following conditions:
 12 
 13 The above copyright notice and this permission notice shall be
 14 included in all copies or substantial portions of the Software.
 15 
 16 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 17 EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 18 MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 19 IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 20 CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 21 TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 22 SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 23 
 24 Retrieved from: http://en.literateprograms.org/Turing_machine_simulator_(C)?oldid=10481
 25 */
 26 
 27 #include <stdio.h>

 28 #include <stdlib.h>

 29 
 30 #include <string.h>

 31 #include "simulate_turing_machine.h"

 32 
 33 struct turing_machine get_example_turing_machine(void) {
 34     struct turing_machine machine;
 35     int i, j;
 36     machine.initial_control_state = 0;
 37     machine.blank_symbol = '#';
 38     machine.num_accepting_states = 1;
 39     machine.accepting_states = malloc(sizeof(int)*machine.num_accepting_states);
 40     if (machine.accepting_states == NULL) {
 41         printf("Out of memory");
 42         exit(-1);
 43     }
 44     machine.accepting_states[0] = 5;
 45     #define NUM_STATES 7

 46     #define STATE_INVALID 6

 47 
 48     machine.transition_table = malloc(sizeof(struct transition_result *) * NUM_STATES);
 49     if (machine.transition_table == NULL) {
 50         printf("Out of memory");
 51         exit(-1);
 52     }
 53     for (i=0; i<NUM_STATES; i++) {
 54         machine.transition_table[i] =
 55             malloc(sizeof(struct transition_result)*TAPE_ALPHABET_SIZE);
 56         if (machine.transition_table[i] == NULL) {
 57             printf("Out of memory");
 58             exit(-1);
 59         }
 60         for (j=0; j<TAPE_ALPHABET_SIZE; j++) {
 61             machine.transition_table[i][j].control_state = STATE_INVALID;
 62             machine.transition_table[i][j].write_symbol = machine.blank_symbol;
 63             machine.transition_table[i][j].dir = DIR_LEFT;
 64         }
 65     }
 66     machine.transition_table[0]['#'].control_state = 4;
 67     machine.transition_table[0]['#'].write_symbol  = '#';
 68     machine.transition_table[0]['#'].dir           = DIR_RIGHT;
 69 
 70     machine.transition_table[0]['a'].control_state = 1;
 71     machine.transition_table[0]['a'].write_symbol  = '#';
 72     machine.transition_table[0]['a'].dir           = DIR_RIGHT;
 73 
 74     machine.transition_table[4]['#'].control_state = 5;
 75     machine.transition_table[4]['#'].write_symbol  = '#';
 76     machine.transition_table[4]['#'].dir           = DIR_RIGHT;
 77 
 78     machine.transition_table[1]['a'].control_state = 1;
 79     machine.transition_table[1]['a'].write_symbol  = 'a';
 80     machine.transition_table[1]['a'].dir           = DIR_RIGHT;
 81 
 82     machine.transition_table[1]['b'].control_state = 1;
 83     machine.transition_table[1]['b'].write_symbol  = 'b';
 84     machine.transition_table[1]['b'].dir           = DIR_RIGHT;
 85 
 86     machine.transition_table[1]['#'].control_state = 2;
 87     machine.transition_table[1]['#'].write_symbol  = '#';
 88     machine.transition_table[1]['#'].dir           = DIR_LEFT;
 89 
 90     machine.transition_table[2]['b'].control_state = 3;
 91     machine.transition_table[2]['b'].write_symbol  = '#';
 92     machine.transition_table[2]['b'].dir           = DIR_LEFT;
 93 
 94     machine.transition_table[3]['a'].control_state = 3;
 95     machine.transition_table[3]['a'].write_symbol  = 'a';
 96     machine.transition_table[3]['a'].dir           = DIR_LEFT;
 97 
 98     machine.transition_table[3]['b'].control_state = 3;
 99     machine.transition_table[3]['b'].write_symbol  = 'b';
100     machine.transition_table[3]['b'].dir           = DIR_LEFT;
101 
102     machine.transition_table[3]['#'].control_state = 0;
103     machine.transition_table[3]['#'].write_symbol  = '#';
104     machine.transition_table[3]['#'].dir           = DIR_RIGHT;
105 
106 
107     return machine;
108 }   
109 
110 
111 int main(int argc, char* argv[]) {
112     if (argc < 1 + 1) {
113         printf("Syntax: simulate_turing_machine <input string>\n");
114         return -1;
115     }
116     simulate(get_example_turing_machine(), strlen(argv[1]), argv[1]);
117     return 0;
118 }
119


Retrieved from "http://en.literateprograms.org/Special:Downloadcode"
Views
Personal tools