[SOLVED] Rust if else and user input

Question

Where did i wrong here

use std::io;

fn main() {
println!("Welcome to Guessing number game");

println!("Would you like to start the game? (y/n)");
let mut is_start = String::new();

io::stdin()
.read_line(&mut is_start)
.expect("Failed to read line.");

if is_start == "y" {
println!("Please input your guess");
} else if is_start == "n" {
println!("Successfully quit the game");
println!("If you want to start game again, please restart your terminal");
} else {
println!("Invalid command");
};

}

When i type y it's not print "Please input your guess" and instead print "Invalid command"

Answer 1

Your input coming from the keyboard will contain the trailing newline character. Before comparing you have to remove that character.

For example:

1)
let is_start = is_start.trim_end();

You need the let because trim_end() will return a different data type.

2)
is_start.truncate(1);

This cuts the length down to one. Disadvantage: it will accept y, yes, yeppediddlidooah, ... everything that start with a y (other letters accordingly)

3)
is_start.truncate(is.start.len()-1);

This chops off the last character. May cause problems on other OSes that use more than a \n to end a line.

Answer 2

Ani Jona 🕊 use your first method, and now it's working. thanks

Answer 3

Your "n" part is not a single expression, wrap it in curlies { }

Answer 4

Sure, you can use a match expression.

Answer 5

I would not expect that much of a difference, let alone any significance! But generally, a match I would expect to be more efficient because it avoids a repeated comparison.

Answer 6

Thanks for your help man Ani Jona 🕊

Answer 7

You're welcome :)

Answer 8

And one more thing

Answer 9

Can i do above checking without if else in rust?

Answer 10

Which one is more efficient is rust match expression or if else above?

Answer 11

match is_start {
"y" => println!("Please input your guess"),
"n" => println!("Successfully quit the game") println!("If you want to start game again, please restart your terminal"),
_ => println!("Invalid command")
};

Why when i do this it give me an error?