Strings in C++ Switch/Case statements

January 10, 2017

Something that used to bug me—used to, because I am so accustomed to work around it that I rarely notice the problem—is that in neither C nor C++ you can use strings (const char * or std::string) in switch/case statement. Indeed, the switch/case statement works only on integral values (an enum, an integral type such as char and int, or an object type with implicit cast to an integral type). But strings aren’t of integral types!

In pure C, we’re pretty much done for. The C preprocessor is too weak to help us built compile-time expression out of strings (or, more exactly, const char *), and there’sn’t much else in the language to help us. However, things are a bit different in C++.

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Log2 (with C++ metaprogramming)

March 22, 2016

C++ meta-programming a powerful tool. Not only can you use it to build generic types (such as the STL’s std::list), you can also use it to have compile-time evaluation. Let’s have a look at a simple problem that can be solved in two very different ways: computing the Log base 2 of an integer.

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