`panic`: The simplest error handling mechanism

The simplest error handling mechanism we will see is panic.

Just like try…except mechanism in python

It prints an error message, starts unwinding the stack, and usually exits the program.

Here, we explicitly call panic on our error condition:

fn drink(beverage: &str) {
    // You shouldn't drink too much sugary beverages.
    if beverage == "lemonade" { panic!("AAAaaaaa!!!!"); }

    println!("Some refreshing {} is all I need.", beverage);
}

fn main() {
    drink("water");
    drink("lemonade");
}