Determinación del número de armstrong en c

#include<stdio.h>
#include<conio.h>
void arm(int a);
int main()
{
	int a;
	printf("\t\t\tEnter a number\n\t\t\t ");
	scanf("%d",&a);
	arm (a);
	getch();
	return 0;
}
void arm(int a)
{
	int b,sum,remainder;
	b=a;
	while (a>0)
	{
		remainder=a%10;
		sum=sum+(remainder*remainder*remainder);
		a=(a-remainder)/10;
	}
	if (b==sum)
	{
		printf("\t\nIt is armstrong number\n");
	}
	else
	{
		printf("\n\tIt is not armstrong number\n");
	}
}
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