When the argument list for a class template is missing, it means that you have not provided the necessary arguments while instantiating the template. In HTML terms, when creating a div element, you need to specify the class attribute to define its style or behavior. Similarly, when using a class template, you need to provide the required arguments to define the behavior or data types used by the template.
Let’s take an example to understand this. Suppose we have a class template called “Array” that represents a dynamic array. The template requires two arguments – the data type of the array elements and the maximum size of the array. Here’s how the class template may look like:
template <typename T, int Size>
class Array {
// Implementation of Array class
};
Now, let’s say we want to create an array of integers with a maximum size of 10. To instantiate the template, we need to provide the required arguments like this:
Array<int, 10> myArray;
In the above example, we provided the data type “int” and the maximum size “10” as arguments while creating the object “myArray” of the “Array” class template.
If we forget to provide the necessary arguments, we will encounter the error “argument list for class template is missing”. For example, if we mistakenly instantiate the class template without providing the required arguments, like this:
Array myArray; // Missing required arguments
This code will result in a compilation error because the compiler expects the necessary arguments to define the behavior of the class template.