C Program to Convert Binary Number to Octal

//C program to convert octal to decimal
#include <stdio.h>
#include <math.h>
long long convertOctalToDecimal(int octnum);
int main()
{
    int octnum;
    printf("Enter an octal number: ");
    scanf("%d", &octnum);
    printf("%d in octal = %d in decimal", octnum, convertOctalToDecimal(octnum));
    return 0;
}
long long convertOctalToDecimal(int octnum)
{
    int decinum = 0, i = 0;
    while(octnum != 0)
    {
        decinum += (octnum%10) * pow(8,i);
        ++i;
        octnum/=10;
    }
    i = 1;
    return decinum;
}