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34 lines
628 B
Rust
34 lines
628 B
Rust
// iterators4.rs
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// Execute `rustlings hint iterators4` or use the `hint` watch subcommand for a hint.
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pub fn factorial(num: u64) -> u64 {
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let _not_use: u64 = (1..=num).product();
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// result is the same
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(1..=num).fold(1, |acc, v| acc * v)
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}
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#[cfg(test)]
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mod tests {
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use super::*;
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#[test]
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fn factorial_of_0() {
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assert_eq!(1, factorial(0));
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}
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#[test]
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fn factorial_of_1() {
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assert_eq!(1, factorial(1));
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}
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#[test]
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fn factorial_of_2() {
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assert_eq!(2, factorial(2));
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}
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#[test]
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fn factorial_of_4() {
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assert_eq!(24, factorial(4));
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}
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}
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