#![allow(unused_must_use)] #![warn(write_literal)] use std::io::Write; fn main() { let mut v = Vec::new(); // these should be fine write!(&mut v, "Hello"); writeln!(&mut v, "Hello"); let world = "world"; writeln!(&mut v, "Hello {}", world); writeln!(&mut v, "3 in hex is {:X}", 3); writeln!(&mut v, "2 + 1 = {:.4}", 3); writeln!(&mut v, "2 + 1 = {:5.4}", 3); writeln!(&mut v, "Debug test {:?}", "hello, world"); writeln!(&mut v, "{0:8} {1:>8}", "hello", "world"); writeln!(&mut v, "{1:8} {0:>8}", "hello", "world"); writeln!(&mut v, "{foo:8} {bar:>8}", foo="hello", bar="world"); writeln!(&mut v, "{bar:8} {foo:>8}", foo="hello", bar="world"); writeln!(&mut v, "{number:>width$}", number=1, width=6); writeln!(&mut v, "{number:>0width$}", number=1, width=6); // these should throw warnings writeln!(&mut v, "{} of {:b} people know binary, the other half doesn't", 1, 2); write!(&mut v, "Hello {}", "world"); writeln!(&mut v, "Hello {} {}", world, "world"); writeln!(&mut v, "Hello {}", "world"); writeln!(&mut v, "10 / 4 is {}", 2.5); writeln!(&mut v, "2 + 1 = {}", 3); // positional args don't change the fact // that we're using a literal -- this should // throw a warning writeln!(&mut v, "{0} {1}", "hello", "world"); writeln!(&mut v, "{1} {0}", "hello", "world"); // named args shouldn't change anything either writeln!(&mut v, "{foo} {bar}", foo="hello", bar="world"); writeln!(&mut v, "{bar} {foo}", foo="hello", bar="world"); }