Armstrong number

#include <stdio.h>
#include <math.h>

int main(){
    int n, tmp = 0, t, d;
    scanf("%d", &n);
    int i = 0;
    while(tmp < n){
        tmp = 0;
        t = n;
        while(t > 0){
            d = t%10;
            tmp += pow(d, i);
            t /= 10;
        }
        i++;
    }

    if(tmp == n){
        printf("%d is an armstrong number\n", n);
    } else{
        printf("%d is not an armstrong number\n", n);
    }
}