图C中的图灵机实现
我正在用正式语言理论学习图灵机我的课程，教授建议运行以下算法来详细查看“TM”背后的逻辑，但是在尝试编译时不起作用告诉我以下错误。
C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `Tape* insert_tape(Tape*, Direction, char)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|44|error: invalid conversion from `void*' to `Tape*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `Tape* create_tape(char*)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|68|error: invalid conversion from `void*' to `Tape*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `Transition* get_transition(char*)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|80|error: invalid conversion from `void*' to `Transition*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `List* insert_list(List*, char*)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|93|error: invalid conversion from `void*' to `List*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `List* insert_list_transition(List*, Transition*)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|105|error: invalid conversion from `void*' to `List*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c||In function `TM* createTM(char*)':| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|166|error: invalid conversion from `void*' to `TM*'| C:\Documents and Settings\Melkhiah.EQUIPO01\Mis documentos\Downloads\Tarea3 Discretas\TM.c|167|error: invalid conversion from `void*' to `List*'| ||=== Build finished: 7 errors, 0 warnings ===| 这是代码：
/* This C file implements a Non-determinitic Pushdown Automata * author: Kevin Zhou * Computer Science and Electronics * University of Bristol * Date: 21st April 2010 */ #include #include #include typedef struct tapes { struct tapes *left; struct tapes *right; char content; } Tape; typedef enum { LEFT,RIGHT } Direction; typedef struct transition { char current_state; char tape_symbol; char new_state; char new_tape_symbol; Direction dir; } Transition; typedef struct list { Transition *content; struct list *next; } List; typedef struct tm { char *input_alpha; char *input; char *tape_alpha; char start; char accept; char reject; List *transition; } TM; Tape *insert_tape(Tape *t, Direction dir, char c) { Tape *head = t; Tape *new1 = calloc(1,sizeof(Tape));; new1 -> content = c; if(dir == LEFT) { while(t->left != NULL) { t = t->left; } new1->right = t; new1->left = NULL; t->left = new1; return new1; } if(dir == RIGHT) { while(t->right != NULL) { t = t->right; } new1->left = t; new1->right = NULL; t->right = new1; } return head; } Tape *create_tape(char *input) { int i=1; Tape *t = calloc(1,sizeof(Tape)); t->content = input[0]; while(1) { if(input[i] == '\0') break; t = insert_tape(t,RIGHT,input[i]); i++; } return t; } /* turn the input string into Transition fields */ Transition *get_transition(char *s) { Transition *t = calloc(1,sizeof(Transition)); Direction dir; t->current_state = s[0]; t->tape_symbol = s[1]; t->new_state = s[2]; t->new_tape_symbol = s[3]; dir = (s[4]=='R')? RIGHT:LEFT; t->dir = dir; return t; } /* turn the string into transitions and add into list */ List *insert_list( List *l, char *elem ) { List *t = calloc(1,sizeof(List)); List *head = l; while(l->next!=NULL) l = l->next; t->content = get_transition(elem); t->next = NULL; l->next = t; return head; } /* insert a transition into a list */ List *insert_list_transition( List *l, Transition *tr) { List *t = calloc(1,sizeof(List)); List *head = l; while(l->next!=NULL) l = l->next; t->content = tr; t->next = NULL; l->next = t; return head; } void print_tape( Tape *t,char blank) { char c; while(1) { if(t->content != blank) break; t= t->right; } while(1) { if(t==NULL) break; c = t->content; if(t->content != blank) putchar(c); t= t->right; } putchar('\n'); } void print_transition (Transition *t) { char s1[] = "Left"; char s2[] = "Right"; if(t==NULL) { printf("NULL Transfer"); return; } printf("current:%c tape:%c new state:%c new tape:%c direction %s\n",t->current_state,t->tape_symbol,t->new_state,t->new_tape_symbol,(t->dir == LEFT)?s1:s2); } /*test if the char c is in the string s */ int contains ( char c, char *s ) { int i=0; while(1) { if(c== s[i]) return 1; if(s[i] == '\0') return 0; i++; } } /* test if the input is a valid input */ int is_valid_input( char *input_alpha, char *input ) { int i=0; char c; while(1) { c = input[i]; if(c == '\0') break; if(!contains(c,input_alpha)) return 0; i++; } return 1; } TM *createTM (char *input) { TM *m = calloc(1,sizeof(TM)); List *tr = calloc(1,sizeof(List)); char *buffer; /*read input alphabet of PDA*/ buffer = strtok(input,":"); if(buffer == NULL) { printf("Error in reading input alphabet!\n"); exit(1); } m->input_alpha = buffer; /*read tape alphabet*/ buffer = strtok(NULL,":"); if(buffer == NULL) { printf("Error in reading tape alphabet!\n"); exit(1); } m->tape_alpha = buffer; /*read input sequence*/ buffer = strtok(NULL,":"); if(buffer == NULL) { printf("Error in reading input sequence!\n"); exit(1); } if(!is_valid_input(m->input_alpha,buffer)) { printf("Error! Input contains some invalid characters that don't match the input alphabet!\n"); exit(1); } m->input = buffer; buffer = strtok(NULL,":"); m->start = buffer[0]; buffer = strtok(NULL,":"); m->accept = buffer[0]; buffer = strtok(NULL,":"); m->reject = buffer[0]; /*read tape transition*/ while(1) { buffer = strtok(NULL,":"); if(buffer == NULL) break; tr = insert_list(tr,buffer); } m->transition = tr->next; return m; } Transition *find_transition(List * list,char state, char tape_symbol) { Transition *t; while(1) { if(list==NULL) return NULL; t = list -> content; if(t->current_state == state && t->tape_symbol == tape_symbol) return t; list = list->next; } } Tape *move(Tape *t,Direction dir, char blank) { if(dir == LEFT) { if(t->left==NULL) { t = insert_tape(t,LEFT,blank); } return t->left; } if(dir == RIGHT) { if(t->right==NULL) { t = insert_tape(t,RIGHT,blank); } return t->right; } return NULL; } void simulate( TM *m ) { /* first symbol in input symbol used to represent the blank symbol */ const char blank = m->tape_alpha[0]; char current_state = m->start; Tape *tape = create_tape(m->input); Tape *current_tape = tape; char current_tape_symbol; Transition *current_transition; while(1) { if(current_state == m->accept) { printf("Accept\n"); print_tape(tape,blank); break; } if(current_state == m->reject) { printf("Reject\n"); print_tape(tape,blank); break; } current_tape_symbol = (current_tape==NULL||current_tape ->content == '\0')?blank:current_tape->content; current_transition = find_transition(m->transition,current_state,current_tape_symbol); current_state = current_transition -> new_state; current_tape -> content = current_transition -> new_tape_symbol; current_tape = move( current_tape, current_transition ->dir, blank); } } int main(void) { char s[300]; TM *p; scanf("%s",s); p = createTM(s); simulate(p); return 0; }
为什么这个程序不起作用？
提供的程序是在C中，但是，您正在使用C ++编译器进行编译。
使用C再次编译，你应该没问题。
代码被视为C ++，因为文件扩展名为.cpp。 将其更改为.c，它应该工作。 这更容易（并且不太可能导致问题）然后开始修改源代码以使其与C ++兼容。
编辑：我假设正在使用的编译器是gcc或cl ，它会根据文件扩展名检测语言。 由于情况并非如此，您必须告诉我们您使用的编译器（和选项）。
编辑2：为了使它与C ++编译器一起使用，你必须像@whitelionV建议一样将new重命名为new1 ，并将所有calloc()返回值强制转换为适当的类型，如下所示：
44 Tape *new1 = (Tape*)calloc(1,sizeof(Tape));; 68 Tape *t = (Tape *)calloc(1,sizeof(Tape)); 80 Transition *t = (Transition *)calloc(1,sizeof(Transition)); 93 List *t = (List *)calloc(1,sizeof(List)); 105 List *t = (List *)calloc(1,sizeof(List)); 166 TM *m = (TM *)calloc(1,sizeof(TM)); 167 List *tr = (List *)calloc(1,sizeof(List));
new是C ++中的保留字，将变量名更改为new1。 或者将.cpp更改为文件名上的c。