Compilare: warning: associated function is never used: `get_i32` --> main.rs:66:8 | 66 | fn get_i32(&mut self) -> i32 { | ^^^^^^^ | = note: `#[warn(dead_code)]` on by default warning: unused `std::result::Result` that must be used --> main.rs:131:5 | 131 | output.write_all(format!("{}\n", graph.len()).as_bytes()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: `#[warn(unused_must_use)]` on by default = note: this `Result` may be an `Err` variant, which should be handled warning: unused `std::result::Result` that must be used --> main.rs:133:9 | 133 | output.write_all(format!("{} {}\n", edge.0, edge.1).as_bytes()); | ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ | = note: this `Result` may be an `Err` variant, which should be handled warning: 3 warnings emitted