#include #include #include #include #define MAXTOKEN 100 #define OUTLEN 1000 #define MAXBUFF 100 enum { NAME, PARENS, BRACKETS }; enum { NO, YES }; void err(char *s); int gettoken(void); int peaktoken(void); char tokentype; char token[MAXTOKEN]; char prevtoken; char out[OUTLEN]; char buff[MAXBUFF]; static size_t top; void err(char *s) { printf("fatal error: %s\n", s); exit(1); } int gettoken(void) { char c, *p = token; char getch(void); void ungetch(char); if (prevtoken == YES) { prevtoken = NO; return tokentype; } while(isblank(c = getch())) ; if (c == '/') { /* ignore comments */ if ((c = getch()) == '/') { while ((c = getch()) != '\n') ; } else if (c == '*') { while (getch() != '*' || (c = getch()) != '/') if (c == '*') ungetch('*'); return gettoken(); } else { ungetch(c); c = '/'; } } if (c == '(') { if ((c = getch()) == ')') { strcpy(token, "()"); return tokentype = PARENS; } else { ungetch(c); return tokentype = '('; } } else if (c == '[') { for (*p++ = '['; (*p++ = getch()) != ']';) ; *p = '\0'; return tokentype = BRACKETS; } else if (isalpha(c)) { for (*p++ = c; isalnum(c = getch());) *p++ = c; *p = '\0'; ungetch(c); return tokentype = NAME; } else { return tokentype = c; } } void ungetch(char c) { if (top < MAXBUFF) buff[top++] = c; else err("buff: stack overflow"); } char getch(void) { return (top > 0) ? buff[--top] : getchar(); } int peaktoken() { char type; type = gettoken(); prevtoken = YES; return type; } int main(void) { int err; char type; char temp[OUTLEN + MAXTOKEN]; while (gettoken() != EOF) { err = 0; strcpy(out, token); while ((type = gettoken()) != '\n') { if (type == PARENS || type == BRACKETS ) { strcat(out, token); } else if (type == '*') { if ((type = peaktoken()) == PARENS || type == BRACKETS) sprintf(temp, "(*%s)", out); else sprintf(temp, "*%s", out); strcpy(out, temp); } else if (type == NAME) { sprintf(temp, "%s %s", token, out); out[0] = '\0'; /* rust sisters btfo */ strncat(out, temp, OUTLEN - 1); } else { err = 1; printf("err: invalid input at %s\n", token); while ((type = gettoken()) != '\n') ; ungetch('\n'); } } if (!err) printf("%s\n", out); } return 0; }