Lab manuals

                              SYMBOL TABLE WITH SUITABLE HASHING    

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], address[10];

float value;

}s[10];

struct hash

{

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

float value,hvalue;

}h[10];

struct instructions

{

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

float operand;

}t;

struct hashedsymboltable

{

char label[10];

float hvalue;

}ht[10];

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

char a[10];

float val;

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 \nAddress\tLabel\tOpcode\tOperand\n");

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

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

{

flag=0;

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

{

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

{

flag=1;

break;

}

}

if(flag==0)

{

h[n].value=t.operand;

h[n].hvalue=h[n].value*2;

h[n].hvalue=h[n].hvalue/1000;

printf("\n\nValue od h[n].hvalue is %2.3f and h[n].valueis %2.3f",h[n].hvalue,h[n].value);

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

strcpy(h[n].opcode,t.opcode);

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

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

ht[n].hvalue=h[n].hvalue;

n++;

}

else

{

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

}

}

}

void search()

{

printf("\nEnter the Label");

scanf("%s",&a);

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

{

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

{

flag=1;

break;

}

}

if(flag==1)

{

printf("\t\tLABEL\tADDRESS\tHVALUE\t");

printf("\t\t----------------------\n\n");

printf("\t\t%s\t%s\t%2.3f\n",h[i].label,h[i].address,h[i].hvalue);

}

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,ht[i].label)==0)

{

flag=1;

break;

}

}

if(flag==0)

{

printf("\nError");

}

else

{

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

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

h[i].hvalue=h[i].value*2;

h[i].hvalue=h[i].hvalue/1000;

ht[i].hvalue=h[i].hvalue;

}

}

void display()

{

printf("\t\t HASHED SYMBOL TABLE\n");

printf("\t\t--------------------\n\n");

printf("\t\tLABEL\tHASHED VALUE\n\n");

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

{

printf("\t\t%s\t   %2.3f\n",ht[i].label,ht[i].hvalue);

}

printf("\n\n\t\t HASH TABLE\n");

printf("\t\t---------------------------------------");

printf("\n\n\t\tADDRESS\tH.VALUE\tVALUE\tLABEL\tOPCODE\n\n");

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

{

printf("\t\t%s\t%2.3f\t%2.0f\t%s\t%s\t%s\n",h[i].address,h[i].hvalue,h[i].value,h[i].label,h[i].opcode);

}

}

OUTPUT:

Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

1

Enter the

Address Label   Opcode  Operand

1000    START   COPY    4890

Value od h[n].hvalue is 9.780 and h[n].valueis 4890.000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

1

Enter the

Address Label   Opcode  Operand

3000    CLOOP   LDA     5000

Value od h[n].hvalue is 10.000 and h[n].valueis 5000.000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

4

                 HASHED SYMBOL TABLE

                --------------------

                LABEL   HASHED VALUE

                START      9.780

                CLOOP      10.000

                 HASH TABLE

                ---------------------------------------

                ADDRESS H.VALUE VALUE   LABEL   OPCODE

                1000    9.780   4890    START   COPY

                3000    10.000  5000    CLOOP   LDA

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

2

Enter the LabelCLOOP

                LABEL   ADDRESS HVALUE

                CLOOP   3000    10.000

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

3

Enter the label

CLOOP

Enter the Address, Value

2000    2340

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

4               

 HASHED SYMBOL TABLE

                --------------------

                LABEL   HASHED VALUE

                START      9.780

                CLOOP      4.680

                 HASH TABLE

                ---------------------------------------

                ADDRESS H.VALUE VALUE   LABEL   OPCODE

                1000    9.780   4890    START   COPY

                2000    4.680   2340    CLOOP   LDA

 Enter the choice

1.Create

2.Search

3.Modify

4.Display

5.Exit

5

Result

Thus above program executed and output verified.