diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..3ba796d --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +rust-calc/target diff --git a/rust-calc/Cargo.lock b/rust-calc/Cargo.lock new file mode 100644 index 0000000..27e0258 --- /dev/null +++ b/rust-calc/Cargo.lock @@ -0,0 +1,7 @@ +# This file is automatically @generated by Cargo. +# It is not intended for manual editing. +version = 3 + +[[package]] +name = "rust-calc" +version = "0.1.0" diff --git a/rust-calc/Cargo.toml b/rust-calc/Cargo.toml new file mode 100644 index 0000000..4ef3c83 --- /dev/null +++ b/rust-calc/Cargo.toml @@ -0,0 +1,8 @@ +[package] +name = "rust-calc" +version = "0.1.0" +edition = "2021" + +# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html + +[dependencies] diff --git a/rust-calc/src/main.rs b/rust-calc/src/main.rs new file mode 100644 index 0000000..e1d5031 --- /dev/null +++ b/rust-calc/src/main.rs @@ -0,0 +1,380 @@ +use std::{ + ops::{AddAssign, DivAssign, MulAssign, SubAssign}, + process, +}; + +// Provide a conformable way to work with symbols +#[derive(Clone, Debug)] +enum Symbol { + Minus, + Plus, + Multiply, + Divide, + + OpenBracket, + CloseBracket, +} +impl Symbol { + // Checks if the given symbol has priority or not + fn priority(&self) -> bool { + match self { + Symbol::Multiply => true, + Symbol::Divide => true, + + _ => false, + } + } + // Check if it brackets (open or close) + fn bracket(&self) -> bool { + match self { + Symbol::OpenBracket => true, + Symbol::CloseBracket => true, + + _ => false, + } + } + // Check if it's an open bracket + fn open_bracket(&self) -> bool { + match self { + Symbol::OpenBracket => true, + + _ => false, + } + } + // Check if it's an close bracket + fn close_bracket(&self) -> bool { + match self { + Symbol::CloseBracket => true, + + _ => false, + } + } +} + +// Provides a object to hold the number being parsed from the string +struct TmpNum { + s: String, +} +impl TmpNum { + // Simple constructor + pub fn new() -> Self { + Self { s: String::new() } + } + // Add a new char to the list of chars used to describe the number in a base 10 fashion + fn push(&mut self, c: char) { + self.s.push(c); + } + // Returns the float number from the parsed input + fn get(&mut self) -> f64 { + let n = self.s.parse::().ok().expect("number is malformed"); + self.s = String::new(); + + n + } + // Returns the length of the current save number as chars. + fn len(&self) -> usize { + self.s.len() + } +} + +// Takes as argument a string representing the wanted calculation and return a list of symbols and values. +fn parse(pattern: String) -> (Vec, Vec) { + let mut symbols = Vec::new(); + let mut numbers = Vec::new(); + + let mut number = TmpNum::new(); + + // Iteration of the chars + let mut i = 0; + while i < pattern.len() { + let c = pattern.chars().nth(i).expect("some char"); + // Check if the given char is a recognized symbol + let s: Option = match c { + '-' => Some(Symbol::Minus), + '+' => Some(Symbol::Plus), + '*' => Some(Symbol::Multiply), + 'x' => Some(Symbol::Multiply), // This is the second way to express multiplication + '/' => Some(Symbol::Divide), + + '(' => Some(Symbol::OpenBracket), + ')' => Some(Symbol::CloseBracket), + + _ => None, + }; + + match s { + // If the char is a recognized symbol + Some(s) => { + // If the char is a bracket + if s.bracket() { + // Keep track of the number of brackets + let mut nb_bracket = 1; + // Keep track of the new position into the list + let mut i2 = i + 1; + // Loop the rest of the input + while i2 < pattern.len() { + let c2 = pattern.chars().nth(i2).expect("some char"); + // Recognize the brackets from the rest of the input + let s2: Option = match c2 { + '(' => Some(Symbol::OpenBracket), + ')' => Some(Symbol::CloseBracket), + + _ => None, + }; + match s2 { + // If brackets + Some(s2) => { + // If open add the increment + if s2.open_bracket() { + nb_bracket += 1; + // If close decrease the counter and check if it gets to zero + } else if s2.close_bracket() { + nb_bracket -= 1; + if nb_bracket == 0 { + // Save the content of the brackets + let new_pattern = pattern + .get(i..i2) + .expect("expect the sub string") + .to_string(); + // Send it to the parse function + let (tmp_symbols, tmp_numbers) = parse(new_pattern); + // Do the calculation + let tmp_result = calculation(tmp_symbols, tmp_numbers); + // Add the calculated value to the list of numbers + numbers.push(tmp_result); + // Change the position in the list + i = i2; + + // Check the symbol after the closing bracket + let c3 = match pattern.chars().nth(i2 + 1){ + Some(c) => c, + None => break, + }; + if !c3.is_numeric() { + let s2 = match c3 { + '-' => Some(Symbol::Minus), + '+' => Some(Symbol::Plus), + '*' => Some(Symbol::Multiply), + '/' => Some(Symbol::Divide), + + _ => None, + }; + match s2 { + Some(s2) => { + symbols.push(s2); + i += 1; + } + // !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! + // This will be used in case of bracket directly followed by number. + None => { + symbols.push(Symbol::Multiply); + } + } + } + } + } + } + // Not a bracket, do nothing + None => {} + } + // Add counter at the end of the loop + i2 += 1; + } + // If not a bracket but symbol + } else { + // If the length of number is zero, add to the current char to number + // It's in the case of signed numbers + if number.s.len() == 0 { + number.push(c); + // Otherwise add the number and the symbol + } else { + symbols.push(s); + numbers.push(number.get()); + } + } + } + None => { + // It's not a recognized symbol so it must be part of a number + number.push(c); + } + } + + // Increment the list position + i += 1; + } + + // At the end the last number need to be added too. + if number.len() != 0 { + numbers.push(number.get()); + } + + // Return the values + (symbols, numbers) +} + +// Run the calculation based on the 2 different lists of symbols and numbers +fn calculation(symbols: Vec, numbers: Vec) -> f64 { + let mut counter = 0; + let mut n1 = *numbers.get(0).expect("expect at least the first value"); + + // Iterate the list of symbols + + while counter < symbols.len() { + let s = symbols + .get(counter) + .expect("expect at least a symbol value"); + let mut n2 = *numbers + .get(counter + 1) + .expect("expect at least a second value"); + + // If the symbol has priority then simply do the calculation and update n1 + if s.priority() { + match s { + Symbol::Multiply => { + n1.mul_assign(n2); + } + Symbol::Divide => { + n1.div_assign(n2); + } + _ => {} + }; + } else { + // Check the next symbol + let next_s = symbols.get(counter + 1); + match next_s { + Some(ss) => { + // If the next has priority start to check until where the priority calculation goes + if ss.priority() { + let mut counter_2 = counter + 1; + let mut nn1 = *numbers + .get(counter_2) + .expect("during the priority, we expect at least the first value"); + while counter_2 < symbols.len() { + let nn2 = *numbers + .get(counter_2 + 1) + .expect("during the priority, we expect at least the second value"); + + if ss.priority() { + match ss { + Symbol::Multiply => { + nn1.mul_assign(nn2); + } + Symbol::Divide => { + nn1.div_assign(nn2); + } + _ => {} + } + // End of the priority. + // Change the position in the list, save the new value as n1 and stop the priority loop + } else { + counter = counter_2; + n2 = nn1; + break; + } + n2 = nn1; + + // Increment the position in the list + counter_2 += 1; + counter = counter_2; + } + } + } + None => {} + } + + // Run the non prioritized calculation + match s { + Symbol::Minus => { + n1.sub_assign(n2); + } + Symbol::Plus => { + n1.add_assign(n2); + } + _ => {} + } + } + + counter += 1; + } + + n1 +} + +fn main() { + let pattern = match std::env::args().nth(1) { + None => { + println!("Input must be provided"); + process::exit(1) + } + Some(s) => s, + }; + + let (symbols, numbers) = parse(pattern); + + // println!("{:?}", symbols); + // println!("{:?}", numbers); + + if symbols.len() < 1 || symbols.len() + 1 != numbers.len() { + println!( + "The input is malformed {} {} {}", + symbols.len() < 1, + symbols.len() + 1 != numbers.len(), + symbols.len() + ); + process::exit(2); + } + + let res = calculation(symbols, numbers); + println!("{res}"); +} + +#[cfg(test)] +mod tests { + use crate::{calculation, parse}; + + #[test] + fn basics() { + let (s, n) = parse("2+2".to_string()); + + assert_eq!(calculation(s, n), 4.0); + let (s, n) = parse("4-9".to_string()); + assert_eq!(calculation(s, n), -5.0); + let (s, n) = parse("7*3".to_string()); + assert_eq!(calculation(s, n), 21.0); + let (s, n) = parse("9/3".to_string()); + assert_eq!(calculation(s, n), 3.0); + + let (s, n) = parse("15*20".to_string()); + assert_ne!(calculation(s, n), 0.0); + } + + #[test] + fn signs_2() { + let (s, n) = parse("2*4+4".to_string()); + assert_eq!(calculation(s, n), 12.0); + let (s, n) = parse("2+2*4".to_string()); + assert_eq!(calculation(s, n), 10.0); + let (s, n) = parse("30/4-9".to_string()); + assert_eq!(calculation(s, n), -1.5); + } + + #[test] + fn negative_number() { + let (s, n) = parse("-2*4+4".to_string()); + assert_eq!(calculation(s, n), -4.0); + let (s, n) = parse("-2+2*4".to_string()); + assert_eq!(calculation(s, n), 6.0); + } + + #[test] + fn with_1_bracket_set() { + let (s, n) = parse("2*(4+4)*2".to_string()); + assert_eq!(calculation(s, n), 32.0); + let (s, n) = parse("2*(4+4)".to_string()); + assert_eq!(calculation(s, n), 16.0); + let (s, n) = parse("-2*(4+4)".to_string()); + assert_eq!(calculation(s, n), -16.0); + let (s, n) = parse("(4+4)*2".to_string()); + assert_eq!(calculation(s, n), 16.0); + } +}