doc cleanup

Author: Wil Boayue

examples/calculate_implied_volatility.rs

@@ -1,21 +1,12 @@
-use ibapi::contracts::{Contract, SecurityType};
+use ibapi::contracts::Contract;
 use ibapi::Client;
 
 fn main() {
     env_logger::init();
 
     let client = Client::connect("127.0.0.1:4002", 100).expect("connection failed");
 
-    let contract = Contract {
-        symbol: "AAPL".into(),
-        security_type: SecurityType::Option,
-        exchange: "SMART".into(),
-        currency: "USD".into(),
-        last_trade_date_or_contract_month: "20250620".into(), // Expiry date (YYYYMMDD)
-        strike: 240.0,
-        right: "C".into(), // Option type: "C" for Call, "P" for Put
-        ..Default::default()
-    };
+    let contract = Contract::option("AAPL", "20250620", 240.0, "C");
 
     let calculation = client.calculate_implied_volatility(&contract, 25.0, 235.0).expect("request failed");
     println!("calculation: {:?}", calculation);

src/contracts.rs

@@ -203,6 +203,27 @@ impl Contract {
         }
     }
 
+    /// Creates option contract from specified symbol, expiry date, strike price and option type.
+    /// Defaults currency to USD and exchange to SMART.
+    ///
+    /// # Arguments
+    /// * `symbol` - Symbols of the underlying asset.
+    /// * `expiration_date` - Expiration date of option contract (YYYYMMDD)
+    /// * `strike` - Strike price of the option contract.
+    /// * `right` - Option type: "C" for Call, "P" for Put
+    pub fn option(symbol: &str, expiration_date: &str, strike: f64, right: &str) -> Contract {
+        Contract {
+            symbol: symbol.into(),
+            security_type: SecurityType::Option,
+            exchange: "SMART".into(),
+            currency: "USD".into(),
+            last_trade_date_or_contract_month: expiration_date.into(), // Expiry date (YYYYMMDD)
+            strike,
+            right: right.into(), // Option type: "C" for Call, "P" for Put
+            ..Default::default()
+        }
+    }
+
     /// Is Bag request
     pub fn is_bag(&self) -> bool {
         self.security_type == SecurityType::Spread