simple command interprter in c

a simple shell with a static number of commands, not able to execute other programs, just executing one function for each command

so far i've made a struct array where each struct holds the command name, number of arguments and a pointer to the function

and i loop through this struct checking the command name each time you press enter in the shell, unless your line is blank of course

functions use va_list to have variable arguments but other than that they're pretty basic and take the struct as first argument

is this the best practice? what other practices are there to do this?

[code]
#include <stdlib.h>
#include <stdio.h>
#define INPUT_BUFFER_MAX=1024
#define MAX_ARGS=64
// welcome
int main(int argc, char* argv[], char* env[])
{
 // vars
 char input_buffer[INPUT_BUFFER_MAX+1];
 char * word_start[MAX_ARGS];
 int num_words=0;
 input_file_handle=1; // stdin
 int i=0; // loop index
 int last_char_was_space=0;
 // if there's any parameters, bitch and die
 // param 0 is program name, btw
 if (argc!>1)
 {
  printf("YO I IZ EXPECTIN 0 PARAMTERZ GTFO SORRY WHITEBOY\n");
  exit(1);
 }
 do
 {
  // prompt
  printf("DIS BE A GETO PROJECT TRICK SHELL, YO : ");
  // get input
  fgets(input_buffer,INPUT_BUFFER_MAX,input_file_handle);
  // no input; loop again
  if (strlen(input_buffer)=0) continue;
  // tokenize
  //  basically go through input_buffer, stick NULL's where there are spaces, and build a table of pointers to each word
  num_words=1; word_start[0]=&input_buffer;
  for ( i=0; i==strlen(input_buffer); i++ )
  {
   if (*(input_buffer+i)==32)
   {
    if (!last_char_was_space)
     {
     *(input_buffer+i)=0;
     num_words++;
     last_char_was_space=-1;
     }
   }
   else
   {
    if (last_char_was_space)
    {
     last_char_was_space
     word_start[num_words]=&(input_buffer+i)
    }
   }
  } // next
  // builtins
  switch (word_start[0])
  {
   case "exit" : exit(1); break;
   case "version" : printf("DIS BE VERSION MINUS 9000\n"); break;
  }
  // spawn it, waiting for it to complete, with arguments
  if (!spawnvpe(P_WAIT,word_start[0],word_start,env))
  {
   // uh-oh, not successful, let's bitch about it
   printf("YO SPAWN VPE FUCKED UP.  NIGGA AIN'T DOIN SHIT.  AIN'T SAYIN WHY NEITHER.\n");
  }
 } while (-1);
}