How do I customize hashing and equality with std::stack?

Customizing hashing and equality for `std::stack` in C++ allows you to define how two stacks are compared and how they are hashed. This can be useful when working with standard library containers that require these functionalities.
C++, std::stack, hashing, equality, customization, data structures
// Custom stack implementation #include #include #include #include // Custom hash function for std::stack struct StackHash { template std::size_t operator()(const std::stack& s) const { std::size_t seed = 0; auto copy = s; // Create a copy to iterate over while (!copy.empty()) { std::hash hasher; seed ^= hasher(copy.top()) + 0x9e3779b9 + (seed << 6) + (seed >> 2); copy.pop(); } return seed; } }; // Custom equality operator for std::stack template bool operator==(const std::stack& lhs, const std::stack& rhs) { if (lhs.size() != rhs.size()) return false; auto copyLhs = lhs; auto copyRhs = rhs; while (!copyLhs.empty()) { if (copyLhs.top() != copyRhs.top()) return false; copyLhs.pop(); copyRhs.pop(); } return true; } int main() { std::stack stack1, stack2; stack1.push(1); stack1.push(2); stack2.push(1); stack2.push(2); std::cout << "Stacks are equal: " << (stack1 == stack2) << std::endl; StackHash stackHash; std::cout << "Hash of stack1: " << stackHash(stack1) << std::endl; return 0; }

C++ std::stack hashing equality customization data structures

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