$ rustc ReorderColumns.rs error[E0432]: unresolved import `regex` --> ReorderColumns.rs:8:5 | 8 | use regex::Regex; | ^^^^^ maybe a missing crate `regex`? | = help: consider adding `extern crate regex` to use the `regex` crate error[E0425]: cannot find value `args` in this scope --> ReorderColumns.rs:28:5 | 28 | if args.len() < 2 { | ^^^^ not found in this scope | help: consider importing this function | 8 + use std::env::args; | error[E0425]: cannot find function `exit` in this scope --> ReorderColumns.rs:30:3 | 30 | exit(1); | ^^^^ not found in this scope | help: consider importing this function | 8 + use std::process::exit; | error[E0425]: cannot find value `args` in this scope --> ReorderColumns.rs:35:15 | 35 | while i <= (args.len() - 1) { | ^^^^ not found in this scope | help: consider importing this function | 8 + use std::env::args; | error[E0425]: cannot find value `Utils` in this scope --> ReorderColumns.rs:36:17 | 36 | colNums.push(Utils.stoiWithDefault(args[i], 0)); | ^^^^^ not found in this scope error[E0425]: cannot find value `args` in this scope --> ReorderColumns.rs:36:39 | 36 | colNums.push(Utils.stoiWithDefault(args[i], 0)); | ^^^^ not found in this scope | help: consider importing this function | 8 + use std::env::args; | error[E0425]: cannot find function `split` in this scope --> ReorderColumns.rs:11:27 | 11 | let fields:Vec<String> = split(line,Regex::new(r"\\t").unwrap()); | ^^^^^ not found in this scope error[E0308]: mismatched types --> ReorderColumns.rs:14:13 | 14 | while i < columns.len() { | - ^^^^^^^^^^^^^ expected `isize`, found `usize` | | | expected because this is `isize` | help: you can convert a `usize` to an `isize` and panic if the converted value doesn't fit | 14 | while i < columns.len().try_into().unwrap() { | ++++++++++++++++++++ error[E0277]: the type `[isize]` cannot be indexed by `isize` --> ReorderColumns.rs:18:15 | 18 | if columns[i] > 0 && columns[i] <= fields.len() { | ^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<isize>` to implement `Index<isize>` error[E0277]: the type `[isize]` cannot be indexed by `isize` --> ReorderColumns.rs:18:33 | 18 | if columns[i] > 0 && columns[i] <= fields.len() { | ^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<isize>` to implement `Index<isize>` error[E0277]: the type `[isize]` cannot be indexed by `isize` --> ReorderColumns.rs:19:33 | 19 | print!("{}", fields[columns[i] - 1]); | ^ slice indices are of type `usize` or ranges of `usize` | = help: the trait `SliceIndex<[isize]>` is not implemented for `isize` = help: the trait `SliceIndex<[T]>` is implemented for `usize` = note: required for `Vec<isize>` to implement `Index<isize>` error[E0425]: cannot find function `getline` in this scope --> ReorderColumns.rs:42:8 | 42 | while getline(line) { | ^^^^^^^ not found in this scope error: aborting due to 12 previous errors Some errors have detailed explanations: E0277, E0308, E0425, E0432. For more information about an error, try `rustc --explain E0277`.