// Assignment 3 Assembler Slot 2
Name
Class
Div
Roll No
:
:
:
:
Devendra Marale
TyBsc(Cs)
A
2372033
#include<stdio.h>
#include<stdlib.h>
#include<string.h>
typedef struct node
{
char symb[20];
int decl, used;
struct node *next;
} NODE;
NODE *first, *last;
void
add_symb1 (char *s)
{
NODE *p;
p = (NODE *) malloc (sizeof (NODE));
strcpy (p->symb, s);
p->decl = 1;
p->used = 0;
p->next = NULL;
if (first == NULL)
first = p;
else
last->next = p;
last = p;
}
void
add_symb2 (char *s)
{
NODE *p;
p = (NODE *) malloc (sizeof (NODE));
strcpy (p->symb, s);
p->decl = 1;
p->used = 0;
p->next = NULL;
if (first == NULL)
first = p;
else
last->next = p;
last = p;
}
NODE *
search (char *s)
{
NODE *p;
p = first;
while (p != NULL)
{
if (strcmp (p->symb, s) == 0)
return p;
p = p->next;
}
return NULL;
}
char optab[][6] =
{ "STOP", "ADD", "SUB", "MULT", "MOVER", "MOVEM", "COMP", "BC", "DIV",
"READ", "PRINT" };
int
search_op (char *s)
{
int i;
for (i = 0; i < 1; i++)
if (strcmp (optab[i], s) == 0)
return i;
return -1;
}
int
main ()
{
NODE *p;
FILE *fp;
char buff[80], t1[20], t2[20], t3[20], t4[20], fname[40];
int n, i;
printf ("Enter source file name:");
scanf ("%s", fname);
fp = fopen (fname, "r");
if (fp == NULL)
{
printf ("File not found.\n", fname);
exit (1);
}
while (fgets (buff, 80, fp) != NULL)
{
n = sscanf (buff, "%s %s %s %s", t1, t2, t3, t4);
switch (n)
{
case 2:
if (strcmp (t1, "START") == 0)
break;
i = search_op (t1);
if (i == 9 || i == 10)
{
p = search (t2);
if (p == NULL)
add_symb2 (t2);
else
p->used = 1;
break;
}
p = search (t1);
if (p == NULL)
add_symb1 (t1);
else
p->decl++;
break;
case 3:
i = search_op (t1);
if (i >= 1 && i <= 10)
{
p = search (t3);
if (p == NULL)
add_symb2 (t3);
else
p->used = 1;
break;
}
if (strcmp (t2, "DS") == 0 || strcmp (t2, "DC") == 0)
{
p = search (t1);
if (p == NULL)
add_symb1 (t1);
else
p->decl++;
break;
}
p = search (t1);
if (p == NULL)
add_symb1 (t1);
else
p->decl++;
p = search (t3);
if (p == NULL)
add_symb2 (t3);
else
p->used = 1;
break;
case 4:
p = search (t1);
if (p == NULL)
add_symb1 (t1);
else
p->decl++;
p = search (t4);
if (p == NULL)
add_symb2 (t4);
else
p->used = 1;
}
}
}
fclose (fp);
p = first;
while (p != NULL)
{
if (p->decl != 0
printf ("symb %s
if (p->used == 0
printf ("symb %s
if (p->decl > 1)
printf ("symb %s
p = p->next;
}
return 0;
&& p->used == 0)
declared but not used.\n", p->symb);
&& p->decl == 0)
used but not declared.\n", p->symb);
redeclared\n", p->symb);
/*
Output:
[tya33@cs15 Syspro]$ vi assembler1.c
[tya33@cs15 Syspro]$ cc assembler1.c
[tya33@cs15 Syspro]$ ./a.out
Enter source file name:inp.asm
symb BEGIN declared but not used.
symb NUM redeclared
symb PRINT declared but not used.
symb
symb
symb
symb
symb
symb
*/
MULT declared but not used.
COMP declared but not used.
HUNDRED declared but not used.
HUNDRED redeclared
BC declared but not used.
END declared but not used.