Reading part of a line [duplicate] - input

Question

This question already has answers here:
How to read a string from keyboard on the same line with output? [duplicate]
(2 answers)
Closed 7 years ago.
I'm totally new to Rust, and in fact just started today. (For those who saw my previous deleted question, you have my most sincere apology.)
I'm just trying to build a simple application to sharpen my skills, but I meet a problem. I like to create something where you can just type stuff, and for those who know dunnet, start each line with two larger than signs.
But I haven't really found out how to read the bits after the two signs. I searched on Google and StackOverflow, but this is the best I got:
//Starting a line
fn start(){print!(">>");}
//Seeking input and saving input
fn line_init() -> String
{
use std::io;
use std::io::BufRead;
start();
let mut input = String::new();
let stdin = io::stdin();
stdin.lock().read_line(&mut input).unwrap();
input
}
//Main function
fn main() {
loop
{
print!("{}", line_init());
}
}
But of course, the user input line lands on a new line, which isn't exactly what I want. This is the C++ version of the thing I want (in fact, I'm just duplicating my C++ project in Rust):
cout << ">>";
string input;
getline(cin, input);
Sorry that this post is getting a bit long!

Answer 1

Do you mean that the user sees something like the following on the console?
hello
>>
instead of
>> hello
?
In that case, the problem is that Rust stdout is line-buffered by default, so unless you write a newline, nothing will be printed to the console.
You need to flush the stdout after you write the line prefix:
fn start(){
print!(">>");
io::stdout().flush().unwrap();
}