Implement the Strategy Pattern

Hard Design Patterns & Final Challenges

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Problem Statement

Create a `Strategy` interface with `virtual int execute(int a, int b) = 0`. Implement `AddStrategy` and `MultiplyStrategy`. Create a `Context` class that takes a `Strategy*` and executes it. Read a string (‘add’ or ‘mul’) followed by two integers. Apply the correct strategy and print ‘Result: [val]’.

Input Format

String ('add' or 'mul') and two integers.

Output Format

Print the result of the strategy execution.

Constraints

None

Sample Input

add 5 3

Sample Output

Result: 8

Explanation

The Strategy pattern allows an algorithm's behavior to be selected at runtime by encapsulating interchangeable logic inside class objects.

Starter Code

#include <iostream>
#include <string>

class Strategy {
public:
    virtual int execute(int a, int b) = 0;
};

// Implement Concrete Strategies and Context

int main() {
    // Setup context, inject strategy, execute
    return 0;
}

Limits

Time Limit: 1s
Memory Limit: 256MB

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