52 lines
1.5 KiB
Rust
52 lines
1.5 KiB
Rust
extern crate dispatch;
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use std::io;
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use std::process::exit;
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use dispatch::{Queue, QueuePriority};
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/// Prompts for a number and adds it to the given sum.
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///
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/// Reading from stdin is done on the given queue.
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/// All printing is performed on the main queue.
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/// Repeats until the user stops entering numbers.
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fn prompt(mut sum: i32, queue: Queue) {
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queue.clone().exec_async(move || {
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let main = Queue::main();
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// Print our prompt on the main thread and wait until it's complete
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main.exec_sync(|| {
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println!("Enter a number:");
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});
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// Read the number the user enters
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let mut input = String::new();
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io::stdin().read_line(&mut input).unwrap();
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if let Ok(num) = input.trim().parse::<i32>() {
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sum += num;
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// Print the sum on the main thread and wait until it's complete
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main.exec_sync(|| {
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println!("Sum is {}\n", sum);
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});
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// Do it again!
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prompt(sum, queue);
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} else {
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// Bail if no number was entered
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main.exec_async(|| {
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println!("Not a number, exiting.");
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exit(0);
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});
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}
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});
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}
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fn main() {
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// Read from stdin on a background queue so that the main queue is free
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// to handle other events. All printing still occurs through the main
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// queue to avoid jumbled output.
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prompt(0, Queue::global(QueuePriority::Default));
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unsafe {
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dispatch::ffi::dispatch_main();
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}
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}
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