Quick Rust Comparison
I've been wanting to try out Rust with something very simple as a first pass through the language.
Rust Impressions
Although I didn't do much with functions on this quick pass - I love the ability to not have the order of main in a program to matter.
Super helpful error messages. Here is an example:
warning: value assigned to `temp` is never read --> src/main.rs:4:13 | 4 | let mut temp=0u32; | ^^^^ | = note: `#[warn(unused_assignments)]` on by default = help: maybe it is overwritten before being read?
I know others have said this, but the Rust compiler feels like it was designed to help me code, rather than just throw errors.
Speed?
I decided to write a simple unoptimized version of the fibonacci sequence. My goal was to take enough time to be noticable...
- On my first pass:
Rust runs took 1m34seconds (using cargo run)
Python took more than 6 minutes
C got 7 seconds
Clearly I must have done something wrong...
It turns out that by default it has debug info and checks that slow Rust down. So a
cargo build --release ./target/release/fib
Then it was faster than C.. and I realized I need to turn off C's debug bits too with:
gcc -O2 -s -DNDEBUG to gcc helped. gcc fib.c
- The final results (all approximate):
Python: 6+ minutes.
C: 1.101s
Rust: .95sE
The Rust
fn main() { let mut previous=0u32; let mut current=1u32; let mut temp; let maxvalue = 2000000000u32; for _n in 0..2000000000 { if current >= maxvalue { //Reset! previous=0; current=1; } temp = current; current = previous + current; previous = temp; } println!("{}", current); }
The C
#include <stdio.h> int main() { unsigned long int previous=0; unsigned long int current=1; unsigned long int temp; unsigned long int maxvalue = 2000000000; for ( int n=0; n < 2000000000; n++ ) { if (current >= maxvalue) { //Reset! previous=0; current=1; } temp = current; current = previous + current; previous = temp; } printf("%lu", current); }
