What are few important MQL4 functions?

<p>There is this <a href="https://book.mql4.com/basics/functions">website</a>&nbsp;, which might be helpful for you.</p>

<p id="isPasted">Some important MQL4 functions include special functions like init(), start(), and deinit(), which are essential for program execution, and trade functions such as OrderSend(), OrderClose(), and OrderModify() for managing trades. Other crucial functions include common ones for displaying alerts (Alert(), Comment()), getting account or symbol information (IsConnected(), Symbol()), and managing program flow (Sleep()).&nbsp;</p><p><strong>Special functions</strong></p><ul><li>init(): Initializes the program when it starts.</li><li>start(): The main function that executes for each new price tick.</li><li>deinit(): Cleans up the program when it is terminated. </li></ul><p><strong>Trade functions</strong></p><ul><li>OrderSend(): Opens market orders or places pending orders.</li><li>OrderClose(): Closes a market order.</li><li>OrderModify(): Modifies an existing order's parameters like Stop Loss or Take Profit.</li><li>OrderDelete(): Deletes a pending order. </li></ul><p><strong>Common functions</strong></p><ul><li>Alert(): Displays an alert box with a message.</li><li>Comment(): Displays a message in the corner of the chart.</li><li>Print(): Writes a message to the "Experts" or "Journal" tab.</li><li>IsConnected(): Checks if the connection to the trading server is active.</li><li>SendMail(): Sends an email.</li><li>Sleep(): Pauses the program for a specified number of milliseconds.</li><li>Symbol(): Returns the name of the current symbol. </li></ul>