mirror of https://github.com/rust-lang/rust
83 lines
1.3 KiB
Rust
83 lines
1.3 KiB
Rust
// Test basic functionality of control flow in a const context.
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//@ run-pass
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const X: u32 = 4;
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const Y: u32 = 5;
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const ABS_DIFF: u32 = if X < Y {
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Y - X
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} else {
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X - Y
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};
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const fn abs_diff(a: u32, b: u32) -> u32 {
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match (a, b) {
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(big, little) if big > little => big - little,
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(little, big) => big - little,
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}
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}
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const fn gcd(a: u32, b: u32) -> u32 {
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if b == 0 {
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return a;
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}
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gcd(b, a % b)
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}
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const fn fib(n: u64) -> u64 {
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if n == 0 {
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return 0;
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}
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let mut fib = (0, 1);
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let mut i = 1;
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while i < n {
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fib = (fib.1, fib.0 + fib.1);
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i += 1;
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}
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fib.1
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}
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const fn is_prime(n: u64) -> bool {
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if n % 2 == 0 {
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return false;
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}
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let mut div = 3;
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loop {
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if n % div == 0 {
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return false;
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}
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if div * div > n {
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return true;
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}
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div += 2;
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}
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}
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macro_rules! const_assert {
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($expr:expr) => {
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const _: () = assert!($expr);
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assert!($expr);
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}
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}
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fn main() {
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const_assert!(abs_diff(4, 5) == abs_diff(5, 4));
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const_assert!(ABS_DIFF == abs_diff(5, 4));
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const_assert!(gcd(48, 18) == 6);
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const_assert!(gcd(18, 48) == 6);
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const_assert!(fib(2) == 1);
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const_assert!(fib(8) == 21);
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const_assert!(is_prime(113));
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const_assert!(!is_prime(117));
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}
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