enum MATH {
    ADD,
    SUB,
    MUL,
    DEV,
}

struct Math {
    a: i32,
    b: i32,
}

impl Math {
    fn init(a: i32, b: i32) -> Math {
        return Math { a, b };
    }

    fn calculate(&self, operation: MATH) -> i32 {
        match operation {
            MATH::ADD => return self.a + self.b,
            MATH::SUB => return self.a - self.b,
            MATH::MUL => return self.a * self.b,
            MATH::DEV => {
                if self.b == 0 {
                    return 0;
                } else {
                    return self.a / self.b;
                }
            }
        }
    }

    fn reinit(&mut self, a: i32, b: i32) {
        self.a = a;
        self.b = b;
    }
}

fn main() {
    let operation: MATH = MATH::ADD;
    let mut calculator: Math = Math::init(10, 4);

    print!("ans: {}\n", calculator.calculate(operation));

    calculator.reinit(32, 2);

    println!("ans after reinit: {}", calculator.calculate(MATH::DEV));
}