A C program that generates random sentences

[ecrazed]

Hi,
just started programming in c and I was looking over this question i found in a c programming book, and it generates random sentences with four arrays, Article that should contain all the articles like a , the etc. noun that contains all the noun, verb that contains all verbs, and prepositon which contains the prepositions. the program should contain an array to concatinate all the words ,and should also print the first letter to be upper case and end the sentence with a period.
heres my code( note: I know i am not really good at c right now but i want to improve, and not sure what i am doing is right)

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

int main()
{
	char sentence[1024];
	char *article = {"the", "a", "one", "some", "any"};
	char *noun = {"boy", "girl", "dog", "town" "car"};
	char *verb = {"drove", "jumped", "ran", "walked", "skipped"};
	char *preposition = {"to", "from", "over", "under", "on"};
   
        srand(time(NULL));
	while(sentence != NULL)
	{

          char **sent = {article, noun, verb preposition};
          sent = rand() % 4;
	  strcpy (sentence, (*article+1);
	  strcat (sentence, (*noun+1);
	  strcat (sentence, (*verb+1);
	  strcat (sentence, (*prepostion+1);
 	  strcat (sentence, (*article+1);
	  strcat (sentence, (*noun+1);
	
	  sprintf(sentence,"%s %s %s %s %s %s",article, noun, verb, prepostion,    article, noun);
	  printf("%s\n", sentence);    		
	  article++;
	  noun++;
          prepostion++;
 	  verb++;
	}
		      
}

[tabstop]

So sent can either be a char **, or an array of four char *, or an int (rand()%4); it cannot be all three at the same time. You also probably want article, noun, verb, and preposition to be arrays too.

You need to use rand to pick a random article; then use rand again to pick a random noun; then use rand again to pick a random verb; etc.

There's no reason to use article+1 instead of article[1].

[whiteflags]

There's also the fact that compiling this points out a few obvious mistakes.

C:\Documents and Settings\Owner>gcc -c -Wall -ansi -pedantic foo.c
foo.c: In function 'main':
foo.c:10:2: warning: excess elements in scalar initializer
foo.c:10:2: warning: (near initialization for 'article')
foo.c:10:2: warning: excess elements in scalar initializer
foo.c:10:2: warning: (near initialization for 'article')
foo.c:10:2: warning: excess elements in scalar initializer
foo.c:10:2: warning: (near initialization for 'article')
foo.c:10:2: warning: excess elements in scalar initializer
foo.c:10:2: warning: (near initialization for 'article')
foo.c:11:2: warning: excess elements in scalar initializer
foo.c:11:2: warning: (near initialization for 'noun')
foo.c:11:2: warning: excess elements in scalar initializer
foo.c:11:2: warning: (near initialization for 'noun')
foo.c:11:2: warning: excess elements in scalar initializer
foo.c:11:2: warning: (near initialization for 'noun')
foo.c:12:2: warning: excess elements in scalar initializer
foo.c:12:2: warning: (near initialization for 'verb')
foo.c:12:2: warning: excess elements in scalar initializer
foo.c:12:2: warning: (near initialization for 'verb')
foo.c:12:2: warning: excess elements in scalar initializer
foo.c:12:2: warning: (near initialization for 'verb')
foo.c:12:2: warning: excess elements in scalar initializer
foo.c:12:2: warning: (near initialization for 'verb')
foo.c:13:2: warning: excess elements in scalar initializer
foo.c:13:2: warning: (near initialization for 'preposition')
foo.c:13:2: warning: excess elements in scalar initializer
foo.c:13:2: warning: (near initialization for 'preposition')
foo.c:13:2: warning: excess elements in scalar initializer
foo.c:13:2: warning: (near initialization for 'preposition')
foo.c:13:2: warning: excess elements in scalar initializer
foo.c:13:2: warning: (near initialization for 'preposition')
foo.c:19:11: warning: initialization from incompatible pointer type
foo.c:19:11: warning: excess elements in scalar initializer
foo.c:19:11: warning: (near initialization for 'sent')
foo.c:19:11: warning: excess elements in scalar initializer
foo.c:19:11: warning: (near initialization for 'sent')
foo.c:19:46: error: expected '}' before 'preposition'
foo.c:20:16: warning: assignment makes pointer from integer without a cast
foo.c:21:34: error: expected ')' before ';' token
foo.c:36:1: warning: passing argument 2 of 'strcpy' makes pointer from integer w
ithout a cast
c:\mingw\bin\../lib/gcc/mingw32/4.5.2/../../../../include/string.h:45:39: note:
expected 'const char *' but argument is of type 'int'
foo.c:36:1: error: expected declaration or statement at end of input
foo.c:36:1: error: expected declaration or statement at end of input
foo.c:13:8: warning: unused variable 'preposition'

What's a scalar?
Scalar values are usually quantities. You didn't intend to initialize a scalar value here, but you didn't exactly follow the syntax for initializing an array. So that's why the compiler complains about those variables.

What's an initializer?
An initializer is some value used in an initialization statement. Every array element could have an initializer, but scalars are only supposed to have one so the others aren't used. That's another reason the compiler was able to say what it said.

What about the other compiler messages?
They stem from syntax errors in your code. I see some unbalanced parentheses.

Like tabstop, I also noticed things like this:

 (*p + 1)

This dereferences p, and adds one to the thing it points to. The compiler thinks it's of expression type int.

Of course, it's right. This is not the same as p[1]. Instead:
p + 1 is also a pointer type, pointing to the first object after p.
*(p + 1) is the first object after p.

[nonpuz]

I would also advise doing some bound checking on "sentence" before strcating it a million times with unknown size strings..

Same goes with the rand % 4, why not write a simple macro that calculates the size of the array you are running rand() against, and use that - 1 for your rand % C expression...then you can freely change/the contents of the array without having to manually adjust all the "magic" size numbers you use...the preprocessor is you friend

ex:

#define ARR_SIZ(a) (sizeof (a) / sizeof *(a))