C Program to convert a decimal to octal number

Program

#include<stdio.h>
#include<math.h>
int octal_decimal(int num)
{
	int dec = 0, rem = 0, i = 0;
	while(num != 0)
	{
		rem = num % 10;
		num = num / 10;
		dec = dec + rem * pow(8, i);
		++i;
	}
	return dec;
}
void main()
{
	int num, result;
	printf("Enter a octal number:\t");
	scanf("%d", &num);
	result = octal_decimal(num);
	printf("The decimal equivalent is:\t%d\n", result);
}

Output

Enter a octal number:	128
The decimal equivalent is:	88