Templates in C++

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A template allows writing generic programs, meaning the same code can work with different data types.

Why Use Templates

• Code reusability

• Type safety

• Reduces code duplication

• Supports generic programming

Types of Templates in C++

1. Function Templates

2. Class Templates

1. Function Templates

A function template works with different data types.

Syntax

template <typename T>
return_type function_name(T parameter) {
    // code
}

Example

template <typename T>
T add(T a, T b) {
    return a + b;
}

Usage:

cout << add(5, 10);
cout << add(2.5, 3.5);

2. Class Templates

A class template allows creating classes with different data types.

Syntax

template <class T>
class ClassName {
    T data;
public:
    void set(T value) {
        data = value;
    }
};

Example

template <class T>
class Box {
    T value;
public:
    void set(T v) {
        value = v;
    }
    T get() {
        return value;
    }
};

Usage:

Box<int> b1;
Box b2;

Template Parameters

• typename or class can be used

• Multiple parameters are allowed

Example:

template <class T, class U>

Advantages of Templates

• Works with multiple data types

• Compile-time type checking

• Cleaner and flexible code

Limitations of Templates

• Error messages can be complex

• Increased compilation time

• Code size may increase

Key Points

• Templates support generic programming

• Function templates for functions

• Class templates for classes

• Defined at compile time

Conclusion

Templates are powerful tools in C++ that help create reusable and type-safe generic code.