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  1. use std::fmt;
  2. use std::iter;
  3.  
  4.  
  5. struct LinearFunctionIterator {
  6.     fun: LinearFunction,
  7.     x: i32,
  8.     stop: i32,
  9. }
  10.  
  11. impl LinearFunctionIterator {
  12.     fn new(fun: LinearFunction, begin: i32, stop: i32) -> LinearFunctionIterator {
  13.         LinearFunctionIterator {
  14.             fun: fun,
  15.             x: begin,
  16.             stop: stop,
  17.         }
  18.     }
  19. }
  20.  
  21. impl iter::Iterator for LinearFunctionIterator {
  22.     type Item = f64;
  23.  
  24.     fn next(&mut self) -> Option<Self::Item> {
  25.         if self.x == self.stop {
  26.             return None
  27.         }
  28.  
  29.         let result = self.fun.feed(self.x as f64);
  30.  
  31.         if self.x < self.stop {
  32.             self.x += 1;
  33.         }
  34.         else {
  35.             self.x -= 1;
  36.         }
  37.  
  38.         return Some(result);
  39.     }
  40. }
  41.  
  42.  
  43. struct LinearFunction {
  44.     a: f64,
  45.     b: f64,
  46. }
  47.  
  48. impl LinearFunction {
  49.     fn new(a: f64, b: f64) -> LinearFunction {
  50.         LinearFunction {
  51.             a: a,
  52.             b: b,
  53.         }
  54.     }
  55.  
  56.     fn feed(&self, x: f64) -> f64 {
  57.         self.a * x + self.b
  58.     }
  59. }
  60.  
  61. impl fmt::Display for LinearFunction {
  62.     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
  63.         write!(f, "f(x) = {} * x + {}", self.a, self.b)
  64.     }
  65. }
  66.  
  67. impl iter::IntoIterator for LinearFunction {
  68.     type Item = f64;
  69.     type IntoIter = LinearFunctionIterator;
  70.  
  71.     fn into_iter(self) -> Self::IntoIter {
  72.         LinearFunctionIterator::new(self, 0, 10)
  73.     }
  74. }
  75.  
  76.  
  77. fn main() {
  78.     let fun = LinearFunction::new(2.0, 1.0);
  79.     println!("{}", fun);
  80.  
  81.     for y in fun.into_iter() {
  82.         println!("{}", y.round());
  83.     }
  84. }
Success #stdin #stdout 0s 4472KB
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f(x) = 2 * x + 1
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https://ideone.com/30uZwT
language:
Rust (rust 1.56)
created:
6 years ago
visibility:
public

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