Abstract Operation

#include <iostream>
#include <string>
using namespace std;

/**
 * Operation is an abstract base class.
 * It defines the interface for mathematical operations.
 */
class Operation {
public:
    // Pure virtual function: This makes the class abstract.
    // It must be implemented by any non-abstract derived class.
    virtual int apply(int x) const = 0;

    // Virtual destructor: Essential when deleting derived objects 
    // through a base class pointer to prevent memory leaks.
    virtual ~Operation() {}
};

class SquareOp : public Operation {
public:
    // Implementation of the square logic
    int apply(int x) const override {
        return x * x;
    }
};

class CubeOp : public Operation {
public:
    // Implementation of the cube logic
    int apply(int x) const override {
        return x * x * x;
    }
};

int main() {
    int n;
    string opName;
    
    // Read the integer and the operation name
    if (!(cin >> n >> opName)) return 0;

    Operation* op = nullptr;

    // Factory logic: Instantiate the correct derived class based on input
    if (opName == "square") {
        op = new SquareOp();
    } else if (opName == "cube") {
        op = new CubeOp();
    }

    // Execute the operation polymorphically
    if (op) {
        cout << op->apply(n);
        
        // Clean up dynamic memory
        delete op;
    }

    return 0;
}