不同的电脑执行如下代码可能会有不同的结果。但是我在同一台机器上的结果,java会比rust快5倍。
java代码:
public class Test {private static final int MAX = 10000000;public static void main(String[] args) {test(1, 3.141592653589793, 2.718281828459045, "Addition");test(2, 3.141592653589793, 2.718281828459045, "Subtraction");test(3, 3.141592653589793, 2.718281828459045, "Multiplication");test(4, 3.141592653589793, 2.718281828459045, "Division");}public static void test(int step, double a, double b, String msg) {long startTime = System.currentTimeMillis();double sum = 0;switch (step) {case 1 -> {for (int i = 0; i < MAX; i++) {sum += a + b;}}case 2 -> {for (int i = 0; i < MAX; i++) {sum += a - b;}}case 3 -> {for (int i = 0; i < MAX; i++) {sum += a * b;}}case 4 -> {for (int i = 0; i < MAX; i++) {sum += a / b;}}}long endTime = System.currentTimeMillis();System.out.println(msg + " Time taken: " + (endTime - startTime) + "ms result: " + sum);}
}
java代码的运行结果
Addition Time taken: 15ms result: 5.8598744811975874E7
Subtraction Time taken: 14ms result: 4233108.251312001
Multiplication Time taken: 17ms result: 8.539734223664734E7
Division Time taken: 15ms result: 1.155727349739092E7
fn main() {_test1(1, 3.141592653589793, 2.718281828459045, "Addition");_test1(2, 3.141592653589793, 2.718281828459045, "Subtraction");_test1(3, 3.141592653589793, 2.718281828459045, "Multiplication");_test1(4, 3.141592653589793, 2.718281828459045, "Division");
}
const MAX: usize = 10000000;
fn _test1(step: u8, a: f64, b: f64, msg: &str) {let start = std::time::Instant::now();let mut sum = 0.0;match step {1 => {for _ in 0..MAX {sum += a + b;}}2 => {for _ in 0..MAX {sum += a - b;}}3 => {for _ in 0..MAX {sum += a * b;}}4 => {for _ in 0..MAX {sum += a / b;}}_ => {println!("Invalid step");}}println!("{} Time take: {:?}ms result: {}", msg, start.elapsed().as_millis(), sum);
}
Addition Time take: 82ms result: 58598744.811975874
Subtraction Time take: 75ms result: 4233108.251312001
Multiplication Time take: 73ms result: 85397342.23664734
Division Time take: 70ms result: 11557273.49739092