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[Basic C++]
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| // https://isocpp.org/images/uploads/2-Tour-Basics.pdf | |
| std::cout << __func__ << __FILE__ << __LINE__ << std::endl; | |
| // XXX scalar vs aggregate | |
| const auto foo { 42 }; // valid but {} hints at aggregate (in theory) | |
| const auto foo = 42; | |
| const auto str { "foo" }; | |
| struct Ruler { | |
| std::string name {}; | |
| int reign_begin {}; | |
| int reign_end {}; | |
| }; | |
| // MEMORY MANAGEMENT | |
| // https://isocpp.org/wiki/faq/freestore-mgmt | |
| // - if you need an auto-free in scope, use the stack!! | |
| const Ruler from_stack{ .name{"Clovis I"}, .reign_begin=509, .reign_end=511}; // https://en.cppreference.com/w/cpp/language/aggregate_initialization | |
| // - make_unique (or make_shared) are nearly always superior to both new/malloc() and completely eliminate delete/free() | |
| auto from_unique = std::make_unique<Ruler>(Ruler{ .title{"king"}, .name{"Clovis I"}, .reign_begin=509, .reign_end=511}); | |
| *from_unique.get(); | |
| // - new -> delete | |
| const Ruler* from_new = new Ruler{ .name{"Clovis I"}, .reign_begin=509, .reign_end=511}; | |
| delete from_new; from_new = nullptr; | |
| // - malloc() -> free() | |
| // https://stackoverflow.com/a/67967472/587407 | |
| int* x = new int[5]; // gv gv gv gv gv (gv - garbage value) | |
| int* x = new int[5](); // 0 0 0 0 0 | |
| int* x = new int[5]{}; // 0 0 0 0 0 (Modern C++) | |
| int* x = new int[5]{1,2,3}; // 1 2 3 0 0 (Modern C++) | |
| char* p = new (std::nothrow) char [1048576]; | |
| )if (!p) { /*...*/ } // null pointers are implicitly converted to false | |
| delete p; p = nullptr; | |
| //////////// | |
| enum class Color { red, blue, green }; // enum class hides the "enum" | |
| Color col = Color::red; // no need to mention "enum" 👍 | |
| Color next = static_cast<Color>((static_cast<int>(col) + 1) % 3); // DANGER | |
| //////////// | |
| switch (answer) { | |
| case ’y’: | |
| return true; | |
| case ’n’: | |
| return false; | |
| default: | |
| cout << "Sorry, I don’t understand that.\n"; | |
| ++tries; // increment | |
| } | |
| //////////// | |
| // lambdas | |
| // https://learn.microsoft.com/en-us/cpp/cpp/lambda-expressions-in-cpp | |
| // XXX mutable by copy!! https://stackoverflow.com/a/43129100/587407 | |
| //////////// | |
| // tuples | |
| // exceptions | |
| // https://learn.microsoft.com/en-us/cpp/cpp/errors-and-exception-handling-modern-cpp | |
| #include <exception>; | |
| throw std::invalid_argument("MyFunc argument too large."); | |
| try | |
| { | |
| //... | |
| } | |
| catch (std::exception& e) | |
| { | |
| std::cerr << "exception caught: " << e.what() << std::endl; | |
| } |
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