Can I extend the C++ language by adding features not present in the standard library.

you can extend the C++ language by adding features not present in the standard library. There are a few ways to accomplish this:

1. Operator Overloading:

• You can redefine the behavior of existing C++ operators (like +, -, *, /, etc.) for your custom data types. This allows you to create intuitive syntax for operations specific to your classes.

class Complex {
public:
    // ... (Complex number implementation)

    Complex operator+(const Complex& other) const { 
        // ... (Add two complex numbers)
    }
};

Complex a(1, 2), b(3, 4);
Complex c = a + b;  // Uses the overloaded '+' operator        

2. Template Metaprogramming:

• C++ templates allow you to perform computations and generate code at compile time. You can use this to create highly specialized and optimized code tailored to specific types or values.

template <int N>
struct Factorial {
    static const int value = N * Factorial<N - 1>::value;
};

template <>
struct Factorial {
    static const int value = 1;
};

int result = Factorial::value; // result is 120        

3. Custom Literals:

• Since C++11, you can define custom suffixes for literals (e.g., 123_km for kilometers). This makes your code more expressive and less error-prone.

constexpr long double operator"" _km(long double x) {
    return x * 1000.0;
}

long double distance = 5.6_km; // distance is 5600.0        

4. Language Extensions (Rare):

• In some cases, you might consider creating an extension to the C++ language itself. This is a complex process involving modifying the compiler or creating a preprocessor. It's generally not recommended unless you have a very strong reason.

Important Considerations:

• Standardization: If you're building a feature for widespread use, consider proposing it for inclusion in the C++ standard.
• Maintainability: Extending the language can make your code harder to understand for others. Use these techniques judiciously and document them well.
• Compatibility: Be mindful of how your extensions interact with existing code and libraries.

Alternative:

• External Libraries: If your goal is to provide convenient functionality, creating a well-designed external library might be a more practical and maintainable approach.

Resource : https://levelup.gitconnected.com/c-template-metaprogramming-why-its-so-powerful-but-underutilized-fe49f9c53f54