To convert roman number to it’s decimal equivalent

Description:

In this program we have to take the roman value. This value is converted into a it’s equivalent decimal number.

 Ex:   X=10

Algoritham:

Step 1: Start

Step 2: read the roman numerical as string

Step 3: find length of roman numerical

Step 4: for each charcter in the string

i)                    if(char=I) then decimal=1

ii)                  if(char=V) then decimal=5

iii)                if(char=X) then decimal=10

iv)                if(char=L) then decimal=50

v)                  if(char=C) then decimal=100

vi)                if(char=D) then decimal=500

vii)              if(char=M) then decimal=1000

viii)            otherwise invalid character

Step 5: repeat step 4 until the length of the string

Step 6: k=char[length-1]

Step 7: for each character of decimal string

i)                    if(decimal[i]>dec[i-1]) then k=k-decimal[i-1]

ii)                  else if(decimal[i]=decimal[i-1 or decimal[i]<decimal[i-1) then k=k+decimall[i-1]

Step 8: repate step 7 until the length of decimal string

Step 9: print decimal value

Step 10: Stop

 Program:

        

#include<stdio.h>

#include<conio.h>

#include<string.h>

#include<stdlib.h>

void main()

{

 int *a,len,i,j,k;

 char *rom;

 clrscr();

 printf("Enter the Roman Numeral:");

 scanf("%s",rom);

 len=strlen(rom);

 for(i=0;i<len;i++) // loop will continue until I is not graterthan length.

 {

             if(rom[i]=='I')

             a[i]=1;

             else if(rom[i]=='V')

             a[i]=5;

             else if(rom[i]=='X')

  a[i]=10;

  else if(rom[i]=='L')

  a[i]=50;

             else if(rom[i]=='C')

  a[i]=100;

             else if(rom[i]=='D')

             a[i]=500;

  else if(rom[i]=='M')

  a[i]=1000;

  else

             {

                          printf("\nInvalid Value");

                           getch();

                          exit(0);

            }

}

k=a[len-1];

for(i=len-1;i>0;i--) // loop will continue until I lessthan zero

{

             if(a[i]>a[i-1])  // check the condition

            k=k-a[i-1];

  else if(a[i]==a[i-1] || a[i]<a[i-1])

            k=k+a[i-1];

}

printf("\nIts Decimal Equivalent is:");

printf("%d",k);

getch();

}

Output:

Enter the Roman Numeral:D

Its Decimal Equivalent is:500

Enter the Roman Numeral:X

Its Decimal Equivalent is:10

Enter the Roman Numeral:23

Invalid Value

Conclusion: The program is error free

VIVA QUESATIONS:

1) What is difference between structure and unions ?

Ans : The amount of memory required to store a structure variable is the sum of size all the members in addition to the padding bytes that may be provided by the compiler. In case of a union the amount of memory required is the same as that required by its largest member.

2) What are various operations performed on union ?

Ans:  i)An union variable can be assigned to another union variable

         ii) A union variable can be passed to a function as a parameter

         iii) The address of the union variable can be extracted by using the address of 

               operator (&).