'C' PROGRAM TO FIND THE ISBN CODE

#include<stdio.h>
void main()
{
int isbn[10],i,sum=0,rem;
printf("enter the isbn code :");
for(i=0;i<10;i++)
scanf("%d",&isbn[i]);
for(i=0;i<9;i++)
sum=sum+((i+1)*isbn[i]);
rem=sum%11;
if(rem==isbn[9])
printf("it is an valid isbn code ");
else
printf("it is not an valid isbn code");
}