#include <stdio.h>  /* printf */
#include <stdlib.h> /* malloc,free */

/* MAX is the size of the largest string we can handle */
#define MAX 1000

/* bigstring is a new data type */
typedef  char bigstring[MAX];

/* reverses a string in place
   returns a pointer to the string
*/
char *reverse( char *s) {
  bigstring buf;
  int i,len;
  len = strlen(s);	/* find the length */
  for (i=0;i<len;i++)
     buf[i] = s[len-i-1];
  buf[i]='\0';		/* null terminate!*/
  strcpy(s,buf);	/* put back in to s */
  return(s);
}


char *dreverse( char *s) {
  char *buf;
  int i,len;
  len = strlen(s);

  /* allocate memory */
  buf = malloc(len+1);

  for (i=0;i<len;i++)
     buf[i] = s[len-i-1];
  buf[i]='\0';
  strcpy(s,buf); free(buf); 
  return(s);
}



void main(int argc,char **argv) {
  if (argc<2) {
     printf("Invalid usage - must supply a string\n");
    exit(0);
  }
  printf("%s\n",reverse(argv[1]));
    /*  printf("%s\n",dreverse(argv[1])); */
}