cpp / intermediate
Snippet
Type-Safe Variant Selection
std::variant provides a type-safe alternative to unions. Combined with std::visit, it allows for branching logic that respects the specific type currently stored.
snippet.cpp
cpp
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#include <iostream>#include <variant>#include <string>int main() {std::variant<int, std::string> data = "C++ Standard";// std::visit handles the control flow based on the active typestd::visit([](auto&& arg) {using T = std::decay_t<decltype(arg)>;if constexpr (std::is_same_v<T, int>) {std::cout << "Integer: " << arg << std::endl;} else if constexpr (std::is_same_v<T, std::string>) {std::cout << "String: " << arg << std::endl;}}, data);return 0;}
Breakdown
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std::variant<int, std::string> data = ...
Declares a variable that can hold either an integer or a string safely.
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if constexpr (std::is_same_v<T, int>)
A compile-time conditional check to determine the type of the visitor's argument.