I am trying to create a symbol table in Julia. While i can get create an empty structure pointer in c just by typing
struct xyz *p
but i can’t find any equivalent to it in julia. also how do i parse a structure as function input ?
:symbolname, or Symbol("symbolname")
I think I have not explained myself well… I am trying to create symbol table from scratch… that’s where we use the empty struct to assign pointers for ending or first element… i want to create equivalent of this. i am basically having trouble with data structures in Julia
julia> struct a end
?
type or paste code he# include <stdio.h>
# include <conio.h>
# include <alloc.h>
# include <string.h>
# define null 0
int size=0;
void insert();
void del();
int search(char lab[]);
void modify();
void display();
struct symbtab
{
char label[10];
int addr;
struct symtab *next;
};
struct symbtab *first,*last;
void main()
{
int op;
int y;
char la[10];
clrscr();
do
{
printf("\nSYMBOL TABLE IMPLEMENTATION\n");
printf("1. INSERT\n");
printf("2. DISPLAY\n");
printf("3. DELETE\n");
printf("4. SEARCH\n");
printf("5. MODIFY\n");
printf("6. END\n");
printf("Enter your option : ");
scanf("%d",&op);
switch(op)
{
case 1:
insert();
display();
break;
case 2:
display();
break;
case 3:
del();
display();
break;
case 4:
printf("Enter the label to be searched : ");
scanf("%s",la);
y=search(la);
if(y==1)
{
printf("The label is already in the symbol Table");
}
else
{
printf("The label is not found in the symbol table");
}
break;
case 5:
modify();
display();
break;
case 6:
break;
}
}
while(op<6);
getch();
}
void insert()
{
int n;
char l[10];
printf("Enter the label : ");
scanf("%s",l);
n=search(l);
if(n==1)
{
printf("The label already exists. Duplicate cant be inserted\n");
}
else
{
struct symbtab *p;
p=malloc(sizeof(struct symbtab));
strcpy(p->label,l);
printf("Enter the address : ");
scanf("%d",&p->addr);
p->next=null;
if(size==0)
{
first=p;
last=p;
}
else
{
last->next=p;
last=p;
}
size++;
}
}
void display()
{
int i;
struct symbtab *p;
p=first;
printf("LABEL\tADDRESS\n");
for(i=0;i<size;i++)
{
printf("%s\t%d\n",p->label,p->addr);
p=p->next;
}
}
int search(char lab[])
{
int i,flag=0;
struct symbtab *p;
p=first;
for(i=0;i<size;i++)
{
if(strcmp(p->label,lab)==0)
{
flag=1;
}
p=p->next;
}
return flag;
}
void modify()
{
char l[10],nl[10];
int add, choice, i, s;
struct symbtab *p;
p=first;
printf("What do you want to modify?\n");
printf("1. Only the label\n");
printf("2. Only the address of a particular label\n");
printf("3. Both the label and address\n");
printf("Enter your choice : ");
scanf("%d",&choice);
switch(choice)
{
case 1:
printf("Enter the old label\n");
scanf("%s",l);
printf("Enter the new label\n");
scanf("%s",nl);
s=search(l);
if(s==0)
{
printf("NO such label");
}
else
{
for(i=0;i<size;i++)
{
if(strcmp(p->label,l)==0)
{
strcpy(p->label,nl);
}
p=p->next;
}
}
break;
case 2:
printf("Enter the label whose address is to modified\n");
scanf("%s",l);
printf("Enter the new address\n");
scanf("%d",&add);
s=search(l);
if(s==0)
{
printf("NO such label");
}
else
{
for(i=0;i<size;i++)
{
if(strcmp(p->label,l)==0)
{
p->addr=add;
}
p=p->next;
}
}
break;
case 3:
printf("Enter the old label : ");
scanf("%s",l);
printf("Enter the new label : ");
scanf("%s",nl);
printf("Enter the new address : ");
scanf("%d",&add);
s=search(l);
if(s==0)
{
printf("NO such label");
}
else
{
for(i=0;i<size;i++)
{
if(strcmp(p->label,l)==0)
{
strcpy(p->label,nl);
p->addr=add;
}
p=p->next;
}
}
break;
}
}
void del()
{
int a;
char l[10];
struct symbtab *p,*q;
p=first;
printf("Enter the label to be deleted\n");
scanf("%s",l);
a=search(l);
if(a==0)
{
printf("Label not found\n");
}
else
{
if(strcmp(first->label,l)==0)
{
first=first->next;
}
else if(strcmp(last->label,l)==0)
{
q=p->next;
while(strcmp(q->label,l)!=0)
{
p=p->next;
q=q->next;
}
p->next=null;
last=p;
}
else
{
q=p->next;
while(strcmp(q->label,l)!=0)
{
p=p->next;
q=q->next;
}
p->next=q->next;
}
size--;
}
}
```This is a c code for symbol table i don't care about the display and switch block. I just want to create this program in Julia.the point being? I think you’re not looking for empty struct, you’re looking for Ref() that acts like pointer in C. Where these pointers/references are not initialized but the struct DOES have field, thus not empty
2 Likes
yes
sorry for not being clear
does not look into the code carefully yet, there’s an @enum macro in julia. Or why do you care about whether it’s a struct or not if what you want is a singleton and does not care about strict typing, just OPRATION::UInt8 = opcode, and use the opcode
1 Like
Thanks Solved it