WAP convert a Roman numeral to its decimal equivalent

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#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++)


{


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--)


{


if(a[i]>a[i-1])


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();

}