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POerror in file definition
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copied!<p>Hi this is my fisrt time to read or to write to a file I got errors in defining file to read from help me</p> <pre><code> /* global.h */ #include <stdio.h> /* include declarations for i/o routines */ #include <ctype.h> /* ... and for character test routines */ #include <stdlib.h> /* ... and for some standard routines, such as exit */ #include <string.h> /* ... and for string routines */ #define BSIZE 128 /* buffer size */ #define NONE -1 #define EOS '\0' #define NUM 256 #define DIV 257 #define MOD 258 #define ID 259 #define DONE 260 #define PLUS 243 #define MINUS 255 int tokenval = NONE; /* value of token attribute */ int lineno = 1; struct entry { /* form of symbol table entry */ char *lexptr; int token; }; struct entry symtable[]; /* symbol table */ void init(); /* loads keywords into symtable */ void error(char* m); /* generates all error messages */ int lexan(); /* lexical analyzer */ void parse(); /* parses and translates expression list */ int insert(char *s, int tok); /* returns position of entry for s */ int lookup(char *s); /* returns position of entry for s */ void emit (int t, int tval); /* generates output */ /* init.c */ struct entry keywords[] = { { "div", DIV }, { "mod", MOD, }, { "plus", PLUS }, { "minus", MINUS}, { 0, 0 } }; void init() /* loads keywords into symtable */ { struct entry *p; for (p = keywords; p->token; p++) insert(p->lexptr, p->token); } /* symbol.c */ #define STRMAX 999 /* size of lexemes array */ #define SYMMAX 100 /* size of symbol table */ char lexemes[STRMAX]; int lastchar = - 1; /* last used position in lexemes */ struct entry symtable[SYMMAX]; int lastentry = 0; /* last used position in symtable */ int lookup(char *s) /* returns position of entry for s */ { int p; for (p = lastentry; p > 0; p = p - 1) if (strcmp(symtable[p].lexptr, s) == 0) return p; return 0; } int insert(char *s, int tok) /* returns position of entry for s */ { int len; len = strlen(s); /* strlen computes length of s */ if (lastentry + 1 >= SYMMAX) error ("symbol table full"); if (lastchar + len + 1 >= STRMAX) error ("lexemes array full"); lastentry = lastentry + 1; symtable[lastentry].token = tok; symtable[lastentry].lexptr = &lexemes[lastchar + 1]; lastchar = lastchar + len + 1; strcpy(symtable[lastentry].lexptr, s); return lastentry; } /* lexer.c */ char lexbuf[BSIZE]; int lexan () /* lexical analyzer */ { int t; while(1) { t = fgetc (fs); if (t == ' ' || t == '\t') ; /* strip out white space */ else if (t == '\n') lineno = lineno + 1; else if (isdigit (t)) { /* t is a digit */ ungetc(t, fs); fscanf(fs,"%d", &tokenval); return NUM; } else if (isalpha(t)) { /* t is a letter */ int p, b = 0; while (isalnum(t)) { /* t is alphanumeric */ lexbuf [b] = t; t = fgetchar (fs); b = b + 1; if (b >= BSIZE) error("compiler error"); } lexbuf[b] = EOS; if (t != EOF) ungetc(t, fs); p = lookup (lexbuf); if (p == 0) p = insert (lexbuf, ID); tokenval = p; return symtable[p].token; } else if (t == EOF) return DONE; else { tokenval = NONE; return t; } } } /* emitter.c */ void emit (int t, int tval) /* generates output */ { switch(t) { case '+' : case '-' : case '*' : case '/': fprintf(ft,"%c\n", t); break; case PLUS : fprintf(ft,"PLUS\n"); break; case MINUS : fprintf(ft,"MINUS\n"); break; case DIV: fprintf(ft,"DIV\n"); break; case MOD: fprintf(ft,"MOD\n"); break; case NUM: fprintf(ft,"%d\n", tval); break; case ID: fprintf(ft,"%s\n", symtable[tval].lexptr); break; default: fprintf(ft,"token %d, tokenval %d\n", t, tval); } } /* parser.c -- without the optimizations */ int lookahead; void match(int); void start(), list(), expr(), moreterms(), term(), morefactors(), factor(); void parse() /* parses and translates expression list */ { lookahead = lexan(); start(); } void start () { /* Just one production for start, so we don't need to check lookahead */ list(); match(DONE); } void list() { if (lookahead == '(' || lookahead == ID || lookahead == NUM) { expr(); match(';'); list(); } else { /* Empty */ } } void expr () { /* Just one production for expr, so we don't need to check lookahead */ term(); moreterms(); } void moreterms() { if (lookahead == '+') { match('+'); term(); emit('+', tokenval); moreterms(); } else if (lookahead == '-') { match('-'); term(); emit('-', tokenval); moreterms(); } else { /* Empty */ } } void term () { /* Just one production for term, so we don't need to check lookahead */ factor(); morefactors(); } void morefactors () { if (lookahead == '*') { match('*'); factor(); emit('*', tokenval); morefactors(); } else if (lookahead == '/') { match('/'); factor(); emit('/', tokenval); morefactors(); } else if (lookahead == PLUS) { match(PLUS); factor(); emit(PLUS, tokenval); morefactors(); } else if (lookahead == MINUS) { match(MINUS); factor(); emit(MINUS, tokenval); morefactors(); } else if (lookahead == DIV) { match(DIV); factor(); emit(DIV, tokenval); morefactors(); } else if (lookahead == MOD) { match(MOD); factor(); emit(MOD, tokenval); morefactors(); } else { /* Empty */ } } void factor () { if (lookahead == '(') { match('('); expr(); match(')'); } else if (lookahead == ID) { int id_lexeme = tokenval; match(ID); emit(ID, id_lexeme); } else if (lookahead == NUM) { int num_value = tokenval; match(NUM); emit(NUM, num_value); } else error("syntax error in factor"); } void match(int t) { if (lookahead == t) lookahead = lexan(); else error ("syntax error in match"); } /* error.c */ void error(char* m) /* generates all error messages */ { fprintf(stderr, "line %d: %s\n", lineno, m); exit(EXIT_FAILURE); /* unsuccessful termination */ } /* main.c */ int main(void) { FILE *fs, *ft ; char ch ; fs = fopen ( "d:\\source.txt", "r" ) ; if ( fs == NULL ) { puts ( "Cannot open source file" ) ; exit(0 ) ; } ft = fopen ( "d:\\out.txt","w" ) ; if ( ft == NULL ) { puts ( "Cannot open target file" ) ; exit(0 ) ; } init(); parse(); fclose(ft); fclose(fs); exit(0); /* successful termination */ } </code></pre>

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