Can anyone....

Can anyone please debug the following binary tree program, it flashes two errors:
1: Type mismatch in redeclaration of 'strdup'
2: Tpe mismatch in redeclaration of 'talloc'

Code:

 
    #include<stdio.h>
    #include<ctype.h>
    #include<string.h>
     
    #define MAXWORD 100
    struct tnode *addtree(struct tnode *, char *);
    void treeprint(struct tnode *);
     
    struct tnode
    {
        char *word;
        int count;
        struct tnode *left;
        struct tnode *right;
    };
  
  main()
    {
        struct tnode *root;
        char word[MAXWORD];
     
        root = NULL;
        while(gets(word)!= "\n")
        if(isalpha(word[0]))
        root=addtree(root, word);
        treeprint(root);
    }
     
    struct node *talloc(void);
    char *strdup(char *);
     
    struct tnode *addtree(struct tnode *p, char *w)
    {
        int cond;
     
        if (p==NULL)
        {
              p=talloc();
              p->word=strdup(w);
              p->count=1;
              p->left=p->right=NULL;
         }else if((cond=strcmp(w,p->word))==0)
              p->count++;
         else if(cond < 0)
              p->left = addtree(p->left,w);
         else
              p->right = addtree(p->left,w);
      return p;
    }
     
    void treeprint(struct tnode *p)
    {
          if(p!=NULL)
    {
          treeprint(p->left);
          printf("%4d %s\n",p->count, p->word);
          treeprintf(p->right);
    }
    }
     
    #include<stdlib.h>
     
    struct tnode *talloc(void)
    {
            return (struct tnode *)malloc(sizeof(struct tnode));
    }
     
    char *strdup(char *s)
    {
        char *p;
        p=(char *)malloc(strlen(s)+1);
        if(p!=NULL)
        strcpy(p,s);
        return p;
    }

1. Indentation, learn it. Use it.
2. main returns an int, and so you should have something like return 0; at the bottom of main.
3. gets ... read the FAQ.
4. Compare the prototype of talloc with the definition. Read very carefully.
5. Why is there an include way down at the bottom of your file?


Quzah.

The declaration is in harmony with the defination. I can't find any error....

Originally Posted by quzah

4. Compare the prototype of talloc with the definition. Read very carefully.

Originally Posted by juice

The declaration is in harmony with the defination. I can't find any error....

There is a consonant missing, silly.

Strdup is not a standard function, but very likely there is a function with that name in string.h. Better to use names like "my_strdup" for such stuff.

Originally Posted by quzah

1. Indentation, learn it. Use it.

PLEASE PLEASE PLEASE. For your own good and everyone else's.

Originally Posted by CommonTater

Oh for crying out loud! I just spent the last 15 minutes trying to match what you guys were saying with the OP's code...
Then I finally notice that he's edited the first message to fix the errors... What an incredily stupid and rude thing for him to do.

S/he didn't edit the error out; there is a type mismatch for the declaration and definition of talloc() because of a letter missing in the former.

Originally Posted by MK27

S/he didn't edit the error out; there is a type mismatch for the declaration and definition of talloc() because of a letter missing in the former.

Thanks... how many dozen times did I miss that? (Such a day this is going to be!)

(offending post removed)

Thanx Quzah, Thanx MK. Code is running now.

In line 23 instead of "gets", I tried to use a function getword() which gets a word from the keyboard until EOF is encountered. What is this end of file (EOF) character, and how is it generated? I tried enter key, escape key, tab key, but none of them corresponds to EOF...

Originally Posted by juice

In line 23 instead of "gets", I tried to use a function getword() which gets a word from the keyboard until EOF is encountered. What is this end of file (EOF) character, and how is it generated? I tried enter key, escape key, tab key, but none of them corresponds to EOF...

You should start a new thread when you have a new question. Anyway, EOF is a special value (possibly -1, but don't count on it) the system passes to your program to indicate the possibility of input has terminated.

You can simulate EOF on the console by using ctrl-d (*nix) or ctrl-z (windows). You may have to hit it twice in a row.

BUT since you are looking for a word and terminating on the newline, the newline itself is a better thing to watch for -- most users will find typing a word and hitting enter, not ctrl-d a few times, easier.

Code:

#include <stdio.h>

int readIn (char *buf, int max) {
	int ch, i = 0;
	max--;
	while (1) {
		ch = fgetc(stdin);
		if (i == max || ch == EOF || ch == '\n') {
			buf[i] = '\0';
			return i;
		}
		buf[i++] = ch;
	}
}

int main(int argc, const char *argv[]) {
	char buf[256];
	int n = readIn(buf, 256);

	printf("%d: %s", n, buf);

	return 0;
}

Of course, there is a standard function which does the same thing, and avoid the pitfalls of gets(), namely, fgets().