Thread: declaration parser

this code compiles but doesn't work, if i try to open debugger, it still does not work.

whats wrong?

Code:

#include <stdio.h>
#include <ctype.h>
#include <string.h>

#define MAXTOKEN 100

enum {NAME, PARENS, BRACKETS};

int gettoken(void);
void dcl(void);
void dirdcl(void);

int tokentype;
char token[MAXTOKEN];
char name[MAXTOKEN];
char datatype[MAXTOKEN];

char out[1000];


int main(){
    while (gettoken() != EOF){
        strcpy(datatype, token);
        out[0] = '\0';
        dcl();
        if(tokentype != '\n')
            printf("Syntax error \n");
        printf("%s %s %s", name, out, datatype);

    }

    return 0;
}

int gettoken(void){
    int c, getch(void);
    void ungetch(int);

    char *p = token;

    while( (c = getch()) == ' ' || c == '\t' )
        ;
    if(c == '('){
        if ( (c = getch()) == ')' ){
            strcpy(token, "()");
            return tokentype = PARENS;
        }
        else {
            ungetch(c);
            return tokentype = '(';
        }
    }
    else if ( c == '['){
        for(*p++ = c ; (*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 dcl(void){
    int ns;

    for(ns = 0; gettoken() == '*'; )
        ns++;
    dirdcl();

    while(ns-- > 0)
        strcat(out, " pointer to");
}

void dirdcl(void){
    int type;

    if(tokentype == '(' ){
        dcl();
        if(tokentype != ')' )
            printf("error: missing ) \n");
    } else if (tokentype == NAME)
        strcpy(name, token);
    else
        printf("error: expected name or (dcl) \n");
    while ( (type = gettoken()) == PARENS || type == BRACKETS )
        if (type == PARENS)
            strcat(out, " function returning");
        else {
            strcat(out, " array");
            strcat(out, token);
            strcat(out, " of");
        }
}

Originally Posted by Salem

Not sure what you mean.
After fixing your non-standard getch/ungetch, I get

Code:

$ gcc -g foo.c
$ ./a.out 
int a
a  int
int a[]
a  array[] of int
int (*fn)()
fn  pointer to function returning int

It seems to be the very basic 'decl' program found in K&R

Next time, provide your actual input as well as the program, when saying "it doesn't work".

hello, salem. thanks for the answer, however. i'm not sure of what you mean by "non-standard". i typed out whats in the book K & R and the response when i compile
is a blank command line window which doesn't show anything. What changes did you make to the code?