Converting Octal to Decimal number.c

/* C Program to Convert Octal to Decimal number */
#include<stdio.h>
#include<math.h>

int main()
{
    long int octal,decimal=0;
    int i=0;

    printf("Enter any octal number: ");
    scanf("%ld",&octal);

    while(octal!=0)
    {
        decimal=decimal+(octal%10)*pow(8,i++);
        octal=octal/10;
    }
    printf("The Decimal number is: %ld\n",decimal);
    return 0;
}