CS360: Exam 1: 10/22/97. Question 2 (12 points)

For each of the following pieces of code, explain what the output will be. Assume that the following is typed into standard input:

J S P
HBP
K M P

If the code exits abnormally, state where in the code this happens and why.

A

#include < stdio.h >
#include "fields.h"

main()
{
  IS is;
  int i, j;

  is = new_inputstruct(NULL);
  while(get_line(is) >= 0) {
    j = is->NF-1;
    while (j >= 0) {
      printf("%s ", is->fields[j]);
      j--;
    }
    printf("\n");
  }
}

B

#include < stdio.h >
#include "dlist.h"

main()
{
  char s[100];
  Dlist d, tmp;

  d = make_dl();

  while(gets(s) != NULL) {
    dl_insert_a(d, s);
  }

  dl_traverse(tmp, d) printf("%s\n", tmp->val);
}

C

main()
{
  char buffer[1000];
  char *ptr;
  char *s1 = "JIM";
  char *s2 = "PLANK";
  int *iptr;
 
  ptr = buffer;

  iptr = (int *) ptr;
  *iptr = strlen(s1);
  ptr += sizeof(int);
  strcpy(ptr, s1);
  ptr += strlen(s1);

  iptr = (int *) ptr;
  *iptr = strlen(s2);
  ptr += sizeof(int);
  strcpy(ptr, s2);
  ptr += strlen(s2);

  write(1, buffer, ptr-buffer);
}