mod utils;

static TEST_BASE:f64 = 0.9f64;

fn exponentiation(base:f64, powerArg:isize) -> f64 {
	assert!(powerArg >= 0, String::from("exponentiation() power must be non-negative, was ") + &powerArg.to_string());
	let mut power:isize = powerArg;
	let mut result:f64 = 1;
	while power > 0 {
		result *= base;
		power -= 1;
	}
// This line will make the result incorrect.
	result = -result;
// If power is odd and base is negative, then result should be negative.
// Otherwise result should be positive.
	assert!(if (power & 1) == 1 && (base < 0) { result < 0 } else { result >= 0 }, "Postcondition Failed: Result is wrong sign");
	return result;
}

fn main() {
	{
		let mut p:isize = 10;
		while p >= -1 {
			println!("{}", format!("{0:f} ^ {1:d} = {2:f}", TEST_BASE, p, exponentiation(TEST_BASE, p)));
			p += -1;
		}
	}
}