fn main() { // This is an example of a line comment // Notice how there are two slashes at the beginning of the line // And that nothing written inside these will be read by the compiler // println!("Hello, world!"); // Run it. See? Now try deleting the two slashes, and run it again. /* * This is another type of comment, the block comment. In general, * the line comment is the recommended comment style however the * block comment is extremely useful for debugging */ /* Note, the previous column of `*` was entirely for style. There's no actual need for it. */ // Observe how block comments allow easy expression manipulation // which line comments do not. Deleting the comment delimiters // will change the result: let x = 5 + /* 90 + */ 5; println!("Is `x` 10 or 100? x = {}", x); }