Implement A Symbol Table

AIM:

 To write a C program to implement creation of symbol table.

ALGORITHM:

Step 1: Start the program.

Step 2: Get the choice from the user.

Step 3: If the option is CREATE, get the input and if there is a SYMBOL, place it in the SYMBOL TABLE.

Step 4: If the choice is SEARCH, check the SYMBOL TABLE and display the message appropriately.

Step 5: If the choice is MODIFY, search for the label and change the value of input.

Step 6: If the choice is DISPLAY, set a for loop and display the table with the given input.

Step 7: Stop the program.

SOURCE CODE:

/* CREATION OF SYMBOL TABLE */

#include<stdio.h>

#include<conio.h>

#include<string.h>

void create();

void search();

void modify();

void display();

struct symbol

{

char label[10], adddress[10], value[5];

}s[10];

struct instructions

{

char address[10],label[10],opcode[10],operand[10];

}t;

int ch,n=0,i,flag=0;

char a[10];

void main()

{

char a[10];

int opt;

clrscr();

ch='y';

do

{

printf("\n Enter the choice\n");

printf("1.Create\n2.Search\n3.Modify\n4.Display\n5.Exit\n");

scanf("%d",&opt);

switch(opt)

{

case 1:

create();

break;

case 2:

search();

break;

case 3:

modify();

break;

case 4:

display()

break;

case 5:

exit(0);

break;

}

}

while(opt<5);

getch();

}

void create()

{

printf("\nEnter the Address, Label, Opcode, Operand\n");

scanf("%s%s%s%s",&t.address,&t.label,&t.opcode,&t.operand);

if(strcmp(t.label,"_")!=0)

{

flag=0;

for(i=0;i<=n:i++)

{

if(strcmp(s[i].label,t.label)==0)

{

flag=1;

break;

}

}

if(flag==0)

{

strcpy(s[n].address,t.address);

strcpy(s[n].label,t.label);

strcpy(s[n].value,t.operand);

n++;

}

else

{

printf("\nThe Label is already there");

}

}

}

void search()

{

printf("\nEnter the Label");

scnaf("%s",&a);

for(i=0;i<=n;i++)

{

if(strcmp(a,s[i].label)==0)

{

flag=1;

break;

}

}

if(flag==1)

{

printf("\t\tLABEL\tADDRESS\tVALUE\t\n");

printf("\t\t%s\t%s\t%s\n",s[i].label,s[i].address,s[i].value);

}

else

{

printf("Not Found");

}

}

void modify()

{

char a[10];

flag=0;

printf("\nEnter the label\n");

scanf("%s",&a);

for(i=0;i<=n;i++)

{

if(strcmp(a,s[i].label)==0)

{

flag=1;

break;

}

}

if(flag==0)

{

printf("\nError");

}

else

{

printf("\nEnter the Address, Value\n");

scanf("%s%s",&s[i].address,&s[i].value);

}

}

void display()

{

printf("\t\tLABEL\tADDRESS\tVALUE\t\t\n");

for(i=0;i<=n;i++)

{

printf("\t\t%s\t%s\t%s\t\t\n",s[i].label,s[i].address,s[i].value);

}

}

OUTPUT:

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

1

Enter the Address, Label, Opcode, Operand

1000 COPY START 4890

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

1

Enter the Address, Label, Opcode, Operand

2000 COPY START 2345

The Label is already there

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

1

Enter the Address, Label, Opcode, Operand

2000 CLOOP LDA 9000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

2

Enter the Label COPY

                LABEL   ADDRESS VALUE

                COPY    1000    4890

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

3

Enter the label

CLOOP

Enter the Address, Value

2003 5000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

4

LABEL   ADDRESS VALUE

   COPY    1000    4890

  CLOOP   2003    5000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

5

Result

Thus above program executed and output verified.