Compilare: warning: unused variable: `fileout` --> main.rs:37:13 | 37 | let mut fileout = File::create("adunare.out"); | ^^^^^^^ help: consider using `_fileout` instead | = note: #[warn(unused_variables)] on by default warning: unused variable: `err` --> main.rs:43:13 | 43 | Err(err) => { | ^^^ help: consider using `_err` instead warning: variable does not need to be mutable --> main.rs:37:9 | 37 | let mut fileout = File::create("adunare.out"); | ----^^^^^^^ | | | help: remove this `mut` | = note: #[warn(unused_mut)] on by default warning: unused `std::result::Result` which must be used --> main.rs:41:12 | 41 | fs::write ("adunare.out",format!("{}",v.iter().sum::< i64 > ())); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: #[warn(unused_must_use)] on by default = note: this `Result` may be an `Err` variant, which should be handled