Solved: get input on the same line as question

Rust programming language is highly favored for its performance, memory safety and concurrency. However, being a system programming language, it might sometimes be less intuitive for operations to beginner developers that are more accessible in other high-level languages, such as getting user inputs. This article will addresses the issue of how to get input on the same line as the question in Rust.

Getting user inputs is significant in developing interactive programs or applications. In Rust, we often use the standard input stream, Stdin, provided by the std::io module. However, this might not place the user input on the same line as the question. Let’s see how we can achieve this.

use std::io::{self, Write};
let mut input = String::new();
print!(“Enter your name: “);
io::stdin().read_line(&mut input).unwrap();
let name: String = input.trim().to_string();
println!(“Hello, {}”, name);

A step-by-step breakdown of the code

  • In the first line, we import necessary modules from std::io. The io module provides Rust’s functionality for dealing with various types of input and output.
  • We then declare a mutable String called input. This will hold the user input.
  • The print! macro is used to display the input prompt without a new line at the end. This is important so that the user input can be on the same line as the question.
  • Because the print! function doesn’t automatically flush the stdout buffer, we need to manually flush it using the io::stdout().flush() call. This ensures that the input prompt is displayed immediately.
  • We then use the read_line function from the Stdin struct and pass the reference of input to it. This function reads user input from the console and appends it to our input variable. We also trim the input to remove any trailing newline characters which can interfere with subsequent code.
  • Finally, we print the input given by the user.

Understanding the Stdin struct and the read_line function

The Stdin struct represents a handle to the standard input stream of a process. This struct is used in our code to fetch the user input. This struct comes with various methods that can be used to manipulate the input data.

The most commonly used method of Stdin struct in Rust is the read_line method. The read_line() method in Rust comes under the Read trait. The Read trait is the primary API in Rust for reading bytes. It takes &mut String as parameter where the input string is stored.

Hopefully, we’ve now demystified getting input on the same line as a question in Rust. The next time you are coding a CLI in Rust, remember these steps and code in a user-friendly manner.

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