Error with integers with leading 0s in an if statement

Question

#include <iostream>
using namespace std;

int main() {
int a;
cout << "Enter Password\n";
cin >> a;
if (a == 910)
{
cout << "Access Granted\n";
}
else
cout << "Access Denied";
return 0;
}
How come I can't use a password with a leading 0? For example, I tried setting up the password to be "0910" instead of "910" but it gives me an error. Why does the leading 0 affect it?

Answer 1

0nnn is an octal value, but 9 is obviously *not* a valid octal digit. So 0910 is not a valid integer.

Wouldn't it be much better to compare to a string anyway? You would avoid any such unwanted side-effects, and you would be able to use other alphanumerical characters in your password...

Answer 2

Numbers starting with 0 are octal numbers and 0x hexadecimal...
010 = 8

Answer 3

I don't know why it doesn't work for you but when I input 0910, I get the string "Access Granted"

Answer 4

I am talking about the part in the code when I set "a" equal to 910. if I change it to 0910, it doesn't run. I am looking up the octal and hexadecimal info now and I don't quite get it.