From 8d621729b51c4c8c69e0a688f93a01d14f5dc868 Mon Sep 17 00:00:00 2001
From: Shay Patel <shay@shay.services>
Date: Fri, 15 Aug 2025 08:50:14 +0100
Subject: [PATCH] move methods into Orderbook impl

---
 src/main.rs      |  22 +--
 src/orderbook.rs | 485 ++++++++++++++++++++++++-----------------------
 2 files changed, 256 insertions(+), 251 deletions(-)

diff --git a/src/main.rs b/src/main.rs
index c209cb8..f0205b9 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,11 +1,10 @@
 use std::io;
-use std::collections::BTreeMap;
 use std::str::SplitWhitespace;
 use std::time::SystemTime;
 
 pub mod orderbook;
 
-use crate::orderbook::*;
+use crate::orderbook::Orderbook;
 
 fn read_in_quantity_and_price(split: &mut SplitWhitespace<'_>, quantity: &mut i32, price: &mut Option<i32>) {
     let quantity_opt_str: Option<&str> = split.next();
@@ -37,15 +36,12 @@ fn read_in_quantity_and_price(split: &mut SplitWhitespace<'_>, quantity: &mut i3
 fn main() {
     let mut input_string = String::new();
 
-    let mut ob = Orderbook {
-        bids: BTreeMap::new(),
-        asks: BTreeMap::new(),
-    };
+    let mut ob = Orderbook::new();
 
-    populate_orderbook(&mut ob);
+    ob.populate_orderbook();
     println!();
 
-    list_orders(&ob);
+    ob.list_orders();
 
     while input_string.trim() != "EXIT" {
         input_string.clear();
@@ -73,10 +69,10 @@ fn main() {
 
                 match price_opt {
                     None => {
-                        market_buy(&mut ob, quantity);
+                        ob.market_buy(quantity);
                     },
                     Some(price) => {
-                        limit_buy(&mut ob, quantity, price);
+                        ob.limit_buy(quantity, price);
                     }
                 };
             },
@@ -87,10 +83,10 @@ fn main() {
 
                 match price_opt {
                     None => {
-                        market_sell(&mut ob, quantity);
+                        ob.market_sell(quantity);
                     },
                     Some(price) => {
-                        limit_sell(&mut ob, quantity, price);
+                        ob.limit_sell(quantity, price);
                     }
                 };
             },
@@ -105,7 +101,7 @@ fn main() {
         println!("Executed in {}μs", difference.as_micros());
 
         println!();
-        list_orders(&ob);
+        ob.list_orders();
     }
 
     println!("Program terminating.");
diff --git a/src/orderbook.rs b/src/orderbook.rs
index 784f401..870eef2 100644
--- a/src/orderbook.rs
+++ b/src/orderbook.rs
@@ -11,270 +11,279 @@ fn gen_hashtag_loop(n: usize) -> String {
     return hashtags;
 }
 
-pub fn list_orders(ob: &Orderbook) {
-    println!("===============================");
-    println!();
-    println!("{:<5} {:>13}", "PRICE", "QUANTITY");
-    
-    println!();
-
-    if ob.asks.len() < 5 {
-        for _ in 0..(5 - ob.asks.len()) { println!(); };
-    };
-    
-    for ask in ob.asks.iter().take(5).rev() {
-        println!("${:<4.2} {:>4} {}", ask.0, ask.1, gen_hashtag_loop((*ask.1).try_into().expect("Failed to format i32 as usize.")));
-    };
-    println!("-------------------------------");
-
-    println!("{:.2}bps", (100.0 * ((*ob.asks.first_key_value().expect("One-sided order book.").0 as f32 / *ob.bids.last_key_value().expect("One-sided order book.").0 as f32) - 1.0)));
-
-    println!("-------------------------------");
-    for bid in ob.bids.iter().rev().take(5) {
-        println!("${:<4.2} {:>4} {}", bid.0, bid.1, gen_hashtag_loop((*bid.1).try_into().expect("Failed to format i32 as usize.")));
-    };
-    
-    if ob.bids.len() < 5 {
-        for _ in 0..(5 - ob.bids.len()) { println!(); };
-    };
-
-    println!();
-}
-
-fn create_buy_order(ob: &mut Orderbook, quantity: i32, price: i32) {
-    println!("Placed BUY order ({} @ ${})", quantity, price);
-    match ob.bids.get(&price) {
-        Some(prev_quantity) => {
-            // add to existing order
-            ob.bids.insert(price, quantity + prev_quantity);
-        },
-        None => {
-            // create new order
-            ob.bids.insert(price, quantity);
-        }
-    };
-}
-
-fn create_sell_order(ob: &mut Orderbook, quantity: i32, price: i32) {
-    println!("Placed SELL order ({} @ ${})", quantity, price); 
-    match ob.asks.get(&price) {
-        Some(prev_quantity) => {
-            // add to existing order
-            ob.asks.insert(price, quantity + prev_quantity);
-        },
-        None => {
-            // create new order
-            ob.asks.insert(price, quantity);
-        }
-    };
-}
-
-pub fn market_buy(ob: &mut Orderbook, quantity: i32) {
-    println!("Performing MARKET BUY: {} @ market price", quantity);
-    println!();
-    let mut left_to_buy: i32 = quantity;
-    let mut total_value: i32 = 0;
-    while left_to_buy > 0 {
-        let (p, q) = ob.asks.pop_first().expect("Insufficient sell volume.");
-        if q > left_to_buy {
-            // push back sell order with reduced quantity
-            ob.asks.insert(p, q-left_to_buy);
-            
-            // increase total_value
-            total_value += left_to_buy * p;
-
-            println!("Bought {} @ ${:.2}", left_to_buy, p);
-
-            // reduce left_to_buy
-            left_to_buy = 0;
-        } else {
-            // increase total_value
-            total_value += q*p;
-
-            // reduce left_to_buy
-            left_to_buy -= q;
-
-            println!("Bought {} @ ${:.2}", q, p);
+impl Orderbook {
+    pub fn new() -> Orderbook {
+        Orderbook {
+            bids: BTreeMap::new(),
+            asks: BTreeMap::new(),
         }
     }
-    println!();
-    if quantity > 0 {
-        println!("Bought {} at an average price of ${:.2}", quantity, ((total_value as f32) / (quantity as f32)));
-    } else {
-        println!("Bought 0");
-    };
-}
+   
+    pub fn list_orders(&self) {
+        println!("===============================");
+        println!();
+        println!("{:<5} {:>13}", "PRICE", "QUANTITY");
+    
+        println!();
 
-pub fn market_sell(ob: &mut Orderbook, quantity: i32) {
-    println!("Performing MARKET SELL: {} @ market price", quantity);
-    println!();
-    let mut left_to_sell: i32 = quantity;
-    let mut total_value: i32 = 0;
-    while left_to_sell > 0 {
-        let (p, q) = ob.bids.pop_last().expect("Insufficient buy volume.");
-        if q > left_to_sell {
-            // push back buy order with reduced quantity
-            ob.bids.insert(p, q-left_to_sell);
-            
-            // increase total_value
-            total_value += left_to_sell * p;
+        if self.asks.len() < 5 {
+            for _ in 0..(5 - self.asks.len()) { println!(); };
+        };
+    
+        for ask in self.asks.iter().take(5).rev() {
+            println!("${:<4.2} {:>4} {}", ask.0, ask.1, gen_hashtag_loop((*ask.1).try_into().expect("Failed to format i32 as usize.")));
+        };
+        println!("-------------------------------");
 
-            println!("Sold {} @ ${:.2}", left_to_sell, p);
+        println!("{:.2}bps", (100.0 * ((*self.asks.first_key_value().expect("One-sided order book.").0 as f32 / *self.bids.last_key_value().expect("One-sided order book.").0 as f32) - 1.0)));
 
-            // reduce left_to_sell
-            left_to_sell = 0;
-        } else {
-            // increase total_value
-            total_value += q*p;
+        println!("-------------------------------");
+        for bid in self.bids.iter().rev().take(5) {
+            println!("${:<4.2} {:>4} {}", bid.0, bid.1, gen_hashtag_loop((*bid.1).try_into().expect("Failed to format i32 as usize.")));
+        };
+    
+        if self.bids.len() < 5 {
+            for _ in 0..(5 - self.bids.len()) { println!(); };
+        };
 
-            // reduce left_to_sell
-            left_to_sell -= q;
+        println!();
+    }   
 
-            println!("Sold {} @ ${:.2}", q, p);
-        }
-    }
-    println!();
-    if quantity > 0 {
-        println!("Sold {} at an average price of ${:.2}", quantity, ((total_value as f32) / (quantity as f32)));
-    } else {
-        println!("Sold 0");
-    };
-}
-
-pub fn limit_buy(ob: &mut Orderbook, quantity: i32, price: i32) {
-    println!("Performing LIMIT BUY: {} @ ${}", quantity, price);
-    println!();
-    let mut left_to_buy: i32 = quantity;
-    let mut total_value: i32 = 0;
-    let mut total_quantity: i32 = 0;
-
-    // check the cheapest sell order - if it doesn't exist, or it does but the price is too high, create a new buy order
-    while left_to_buy > 0 {
-        match ob.asks.pop_first() {
+    fn create_buy_order(&mut self, quantity: i32, price: i32) {
+        println!("Placed BUY order ({} @ ${})", quantity, price);
+        match self.bids.get(&price) {
+            Some(prev_quantity) => {
+                // add to existing order
+                self.bids.insert(price, quantity + prev_quantity);
+            },
             None => {
-                // there are no sell orders, so create a new buy order
-                create_buy_order(ob, left_to_buy, price);
+                // create new order
+                self.bids.insert(price, quantity);
+            }
+        };
+    }
+
+    fn create_sell_order(&mut self, quantity: i32, price: i32) {
+        println!("Placed SELL order ({} @ ${})", quantity, price); 
+        match self.asks.get(&price) {
+            Some(prev_quantity) => {
+                // add to existing order
+                self.asks.insert(price, quantity + prev_quantity);
+            },
+            None => {
+                // create new order
+                self.asks.insert(price, quantity);
+            }
+        };
+    }
+
+    pub fn market_buy(&mut self, quantity: i32) {
+        println!("Performing MARKET BUY: {} @ market price", quantity);
+        println!();
+        let mut left_to_buy: i32 = quantity;
+        let mut total_value: i32 = 0;
+        while left_to_buy > 0 {
+            let (p, q) = self.asks.pop_first().expect("Insufficient sell volume.");
+            if q > left_to_buy {
+                // push back sell order with reduced quantity
+                self.asks.insert(p, q-left_to_buy);
+            
+                // increase total_value
+                total_value += left_to_buy * p;
+
+                println!("Bought {} @ ${:.2}", left_to_buy, p);
+
+                // reduce left_to_buy
                 left_to_buy = 0;
-            },
-            Some((p, q)) => {
-                // check if this sell order is cheap enough
-                if p <= price {
-                    // cheap enough, fill order as much as possible
-                    if q > left_to_buy {
-                        // push back sell order with reduced quantity
-                        ob.asks.insert(p, q-left_to_buy);
-            
-                        // increase total_value
-                        total_value += left_to_buy * p;
-                        total_quantity += left_to_buy;
+            } else {
+                // increase total_value
+                total_value += q*p;
 
-                        println!("Bought {} @ ${:.2}", left_to_buy, p);
+                // reduce left_to_buy
+                left_to_buy -= q;
 
-                        // reduce left_to_buy
-                        left_to_buy = 0;
-                    } else {
-                        // increase total_value
-                        total_value += q*p;
-                        total_quantity += q;
-
-                        // reduce left_to_buy
-                        left_to_buy -= q;
-
-                        println!("Bought {} @ ${:.2}", q, p);
-                    }
-                } else {
-                    ob.asks.insert(p, q);
-                    create_buy_order(ob, left_to_buy, price);
-                    left_to_buy = 0;
-                }
+                println!("Bought {} @ ${:.2}", q, p);
             }
         }
+        println!();
+        if quantity > 0 {
+            println!("Bought {} at an average price of ${:.2}", quantity, ((total_value as f32) / (quantity as f32)));
+        } else {
+            println!("Bought 0");
+        };
     }
-    println!();
-    if quantity > 0 {
-        println!("Bought {} at an average price of ${:.2}", quantity, ((total_value as f32) / (total_quantity as f32)));
-    } else {
-        println!("Bought 0");
-    };
-}
 
-pub fn limit_sell(ob: &mut Orderbook, quantity: i32, price: i32) {
-    println!("Performing LIMIT SELL: {} @ ${}", quantity, price);
-    println!();
-    let mut left_to_sell: i32 = quantity;
-    let mut total_value: i32 = 0;
-    let mut total_quantity: i32 = 0;
+    pub fn market_sell(&mut self, quantity: i32) {
+        println!("Performing MARKET SELL: {} @ market price", quantity);
+        println!();
+        let mut left_to_sell: i32 = quantity;
+        let mut total_value: i32 = 0;
+        while left_to_sell > 0 {
+            let (p, q) = self.bids.pop_last().expect("Insufficient buy volume.");
+            if q > left_to_sell {
+                // push back buy order with reduced quantity
+                self.bids.insert(p, q-left_to_sell);
+            
+                // increase total_value
+                total_value += left_to_sell * p;
 
-    // check the most appealing buy order - if it doesn't exist, or it does but the price is too low, create a new sell order
-    while left_to_sell > 0 {
-        match ob.bids.pop_last() {
-            None => {
-                // there are no buy orders, so create a new sell order
-                create_sell_order(ob, left_to_sell, price);
+                println!("Sold {} @ ${:.2}", left_to_sell, p);
+
+                // reduce left_to_sell
                 left_to_sell = 0;
-            },
-            Some((p, q)) => {
-                // check if this buy order is high enough
-                if p >= price {
-                    // fill order as much as possible
-                    if q > left_to_sell {
-                        // push back buy order with reduced quantity
-                        ob.bids.insert(p, q-left_to_sell);
+            } else {
+                // increase total_value
+                total_value += q*p;
+
+                // reduce left_to_sell
+                left_to_sell -= q;
+
+                println!("Sold {} @ ${:.2}", q, p);
+            }
+        }
+        println!();
+        if quantity > 0 {
+            println!("Sold {} at an average price of ${:.2}", quantity, ((total_value as f32) / (quantity as f32)));
+        } else {
+            println!("Sold 0");
+        };
+    }
+
+    pub fn limit_buy(&mut self, quantity: i32, price: i32) {
+        println!("Performing LIMIT BUY: {} @ ${}", quantity, price);
+        println!();
+        let mut left_to_buy: i32 = quantity;
+        let mut total_value: i32 = 0;
+        let mut total_quantity: i32 = 0;
+
+        // check the cheapest sell order - if it doesn't exist, or it does but the price is too high, create a new buy order
+        while left_to_buy > 0 {
+            match self.asks.pop_first() {
+                None => {
+                    // there are no sell orders, so create a new buy order
+                    self.create_buy_order(left_to_buy, price);
+                    left_to_buy = 0;
+                },
+                Some((p, q)) => {
+                    // check if this sell order is cheap enough
+                    if p <= price {
+                        // cheap enough, fill order as much as possible
+                        if q > left_to_buy {
+                            // push back sell order with reduced quantity
+                            self.asks.insert(p, q-left_to_buy);
             
-                        // increase total_value
-                        total_value += left_to_sell * p;
-                        total_quantity += left_to_sell;
+                            // increase total_value
+                            total_value += left_to_buy * p;
+                            total_quantity += left_to_buy;
 
-                        println!("Sold {} @ ${:.2}", left_to_sell, p);
+                            println!("Bought {} @ ${:.2}", left_to_buy, p);
 
-                        // reduce left_to_sell
-                        left_to_sell = 0;
+                            // reduce left_to_buy
+                            left_to_buy = 0;
+                        } else {
+                            // increase total_value
+                            total_value += q*p;
+                            total_quantity += q;
+
+                            // reduce left_to_buy
+                            left_to_buy -= q;
+
+                            println!("Bought {} @ ${:.2}", q, p);
+                        }
                     } else {
-                        // increase total_value
-                        total_value += q*p;
-                        total_quantity += q;
-
-                        // reduce left_to_sell
-                        left_to_sell -= q;
-
-                        println!("Sold {} @ ${:.2}", q, p);
+                        self.asks.insert(p, q);
+                        self.create_buy_order(left_to_buy, price);
+                        left_to_buy = 0;
                     }
-                } else {
-                    ob.bids.insert(p, q);
-                    create_sell_order(ob, left_to_sell, price);
-                    left_to_sell = 0;
                 }
             }
         }
+        println!();
+        if quantity > 0 {
+            println!("Bought {} at an average price of ${:.2}", quantity, ((total_value as f32) / (total_quantity as f32)));
+        } else {
+            println!("Bought 0");
+        };
     }
-    println!();
-    if quantity > 0 {
-        println!("Sold {} at an average price of ${:.2}", quantity, ((total_value as f32) / (total_quantity as f32)));
-    } else {
-        println!("Sold 0");
-    };
-}
 
-pub fn populate_orderbook(ob: &mut Orderbook) {
-    limit_buy(ob, 5, 8);
-    limit_buy(ob, 4, 7);
-    limit_buy(ob, 2, 3);
-    limit_buy(ob, 6, 8);
-    limit_buy(ob, 5, 15);
-    limit_buy(ob, 10, 10);
-    limit_buy(ob, 8, 9);
-    limit_buy(ob, 1, 2);
-    limit_buy(ob, 12, 14);
-    limit_buy(ob, 7, 5);
+    pub fn limit_sell(&mut self, quantity: i32, price: i32) {
+        println!("Performing LIMIT SELL: {} @ ${}", quantity, price);
+        println!();
+        let mut left_to_sell: i32 = quantity;
+        let mut total_value: i32 = 0;
+        let mut total_quantity: i32 = 0;
 
-    limit_sell(ob, 2, 15);
-    limit_sell(ob, 3, 16);
-    limit_sell(ob, 3, 17);
-    limit_sell(ob, 4, 18);
-    limit_sell(ob, 5, 20);
-    limit_sell(ob, 6, 18);
-    limit_sell(ob, 9, 21);
-    limit_sell(ob, 15, 25);
-    limit_sell(ob, 2, 19);
-    limit_sell(ob, 11, 22);
+        // check the most appealing buy order - if it doesn't exist, or it does but the price is too low, create a new sell order
+        while left_to_sell > 0 {
+            match self.bids.pop_last() {
+                None => {
+                    // there are no buy orders, so create a new sell order
+                    self.create_sell_order(left_to_sell, price);
+                    left_to_sell = 0;
+                },
+                Some((p, q)) => {
+                    // check if this buy order is high enough
+                    if p >= price {
+                        // fill order as much as possible
+                        if q > left_to_sell {
+                            // push back buy order with reduced quantity
+                            self.bids.insert(p, q-left_to_sell);
+            
+                            // increase total_value
+                            total_value += left_to_sell * p;
+                            total_quantity += left_to_sell;
+
+                            println!("Sold {} @ ${:.2}", left_to_sell, p);
+
+                            // reduce left_to_sell
+                            left_to_sell = 0;
+                        } else {
+                            // increase total_value
+                            total_value += q*p;
+                            total_quantity += q;
+
+                            // reduce left_to_sell
+                            left_to_sell -= q;
+
+                            println!("Sold {} @ ${:.2}", q, p);
+                        }
+                    } else {
+                        self.bids.insert(p, q);
+                        self.create_sell_order(left_to_sell, price);
+                        left_to_sell = 0;
+                    }
+                }
+            }
+        }
+        println!();
+        if quantity > 0 {
+            println!("Sold {} at an average price of ${:.2}", quantity, ((total_value as f32) / (total_quantity as f32)));
+        } else {
+            println!("Sold 0");
+        };
+    }
+
+    pub fn populate_orderbook(&mut self) {
+        self.limit_buy(5, 8);
+        self.limit_buy(4, 7);
+        self.limit_buy(2, 3);
+        self.limit_buy(6, 8);
+        self.limit_buy(5, 15);
+        self.limit_buy(10, 10);
+        self.limit_buy(8, 9);
+        self.limit_buy(1, 2);
+        self.limit_buy(12, 14);
+        self.limit_buy(7, 5);
+
+        self.limit_sell(2, 15);
+        self.limit_sell(3, 16);
+        self.limit_sell(3, 17);
+        self.limit_sell(4, 18);
+        self.limit_sell(5, 20);
+        self.limit_sell(6, 18);
+        self.limit_sell(9, 21);
+        self.limit_sell(15, 25);
+        self.limit_sell(2, 19);
+        self.limit_sell(11, 22);
+    }
 }
\ No newline at end of file