MQL4｜String Data Type(string)

Usage The string data type is used to represent text strings. For example, strings are necessary for usernames, messages, and currency pair symbols. In MQL4, ASCII strings up to 255 characters can be stored.

Size The size of a string type is variable, with the actual string data being stored elsewhere in memory. As a pointer, it has a size of 8 bytes.

Value Range String types can hold ASCII characters ranging from 0 to 255. This means each character is represented by one byte.

Usage Example Below is an example of using the string type. This example stores strings in variables and outputs them as messages.

void OnStart() {
    // Define strings
    string greeting = "Hello, World!";
    string currencyPair = "USDJPY";

    // Output strings
    Print(greeting);
    Print("The current currency pair is " + currencyPair + ".");

    // Concatenate strings
    string fullMessage = greeting + " The current currency pair is " + currencyPair + ".";
    Print(fullMessage);
}

In this code, the following steps are taken to use the string type:

1. Define string variables greeting and currencyPair, assigning values to them.
2. Use the Print function to output the contents of greeting and currencyPair.
3. Use the + operator to concatenate multiple strings and store them in a new string fullMessage.
4. Output the contents of fullMessage with the Print function.

Thus, the string type is very convenient for handling text data and is widely used when text manipulation or display is required.