C++ Templates Basics

In C++, templates are a feature that allows you to write generic code that can work with any data type. They are often used to create reusable and flexible code that can be applied to different types of data without the need to write separate code for each type.

A template is defined by placing the keyword “template” before the declaration of a function or class, followed by a template parameter list, which specifies the types that the template will work with.

Here’s an example of a simple template function that calculates the maximum of two values:

template <typename T>
T max(T a, T b)
{
    return (a > b) ? a : b;
}

This function can be used with any data type that has the “>” operator defined, such as int, float, or double.

int x = max(3, 4);
float y = max(1.5f, 2.5f);

Templates can also be used with classes, in this case, it’s called a template class:

template <typename T>
class MyArray
{
    T* data;
    int size;
public:
    MyArray(int s) {
        size = s;
        data = new T[size];
    }
    T& operator[](int i) {
        return data[i];
    }
    int getSize() {
        return size;
    }
};

This class can be instantiated with any type, for example:

MyArray<int> myIntArray(10);
MyArray<double> myDoubleArray(5);

Templates can make your code more generic and reusable, but it can also increase the complexity and make the code harder to read and debug. It’s important to use them judiciously and to make sure that the code is well-documented and easily understandable.