why if statement giving wrong results?

i am a noob in programming,i tried writing a program to check if a given 3 digit number is armstrong or not, but at the end the if statement is not giving the desired results.please help.

#include <stdio.h>
#include <stdlib.h>

int main()
{
    int n, i, j = 0, nd = 0;

    printf("enter the 3 digit number:");

    scanf("%d", &n);
    for (i = 0; i = n; i++)
    {
        if (n / 10)!=0)
            {
                nd++;
                n = (n / 10);
            }
        else
        {
            break;
        }
    }
    int digits = nd + 1;
    printf("enter the number with space in between:");
    int ar[digits];
    int qr[digits];
    for (i = 0; i < digits; i++)
    {
        scanf("%d", &ar[i]);
    }
    for (i = 0; i < digits; i++)
    {
        qr[i] = (ar[i] * ar[i] * ar[i]);
    }
    for (i = 0; i < digits; i++)
    {
        j += qr[i];
    }
    printf("%d\n", j);

    //<facing issue here>

        if (j == n)
    {
        printf("the number is armstrong");
    }
    else { printf("the number is not armstrong"); }

    return 0;
}