Is Armstrong Number

#1

Problem: https://online.codingblocks.com/app/player/158507/content/150879/4790/code-challenge#

// Program to check if a number is armstrong number

#include<iostream>
#include<cmath>
using namespace std;

bool checkArm(long long int n)
{
    long long int temp = n;
    int sum = 0;
    while (n>0)
    {
        long long int a = n%10;
        sum += a*a*a;
        n /= 10;
    }
    if (sum == temp)
        return true;
    else
        return false;
}

int main()
{
    long long int n;
    cin>>n;

    if(checkArm(n))
        cout<<"true"<<endl;
    else
        cout<<"false"<<endl;
    return 0;
}

Its giving me errors in Test Case 0 and Test Case 1. But its giving me correct answers. Kindly help!