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#include <iostream>
#include <vector>
#include <memory>

// DEMONSTRATES: what leaks look like and how to fix them

// BAD: leaks on exception path
void leaky(bool throwIt) {
    int* data = new int[1024];
    if (throwIt) throw std::runtime_error("oops");
    delete[] data;   // never reached if exception thrown
}

// GOOD: RAII via vector — never leaks
void safe(bool throwIt) {
    std::vector<int> data(1024);   // owns memory via RAII
    if (throwIt) throw std::runtime_error("oops");
    // data freed automatically whether or not exception thrown
}

// Demonstrates use-after-free (undefined behaviour — don't do this)
void useAfterFree() {
    int* p = new int(42);
    delete p;
    // std::cout << *p;  // UB: reading freed memory
}

int main() {
    // Safe version handles exception cleanly
    try { safe(true); } catch (...) {}

// Smart pointer — zero manual memory management
    auto buf = std::make_unique<int[]>(1024);
    buf[0] = 99;
    std::cout << "buf[0] = " << buf[0] << "
";
    // buf freed here automatically

// Compile with: g++ -fsanitize=address -g -o prog prog.cpp
    // Run: ./prog   (ASan reports any detected errors)

std::cout << "No leaks with RAII and smart pointers
";
    return 0;
}