An expression is a sequence of literals, variables, operators, and function calls that can be evaluated to produce a result. Expressions may represent values, objects, or functions. Expressions are not statements An expression is a block of code that can be evaluated.…
Most template examples use types as template arguments: Here, T is a placeholder for a type such as int, double, or std::string. However, when we create a std::bitset, we specify the number of bits in <> as a literal, not a type. This is the…
Here is the clamp() function template from the previous Nibble: Strangely, this doesn’t compile. The compiler error gives us a clue: template argument deduction/substitution failed During template argument deduction, the compiler tries to deduce one type for T. The template says all three…
The Problem Let’s say we have a function that clamps a value betwen a range. Nice. What about if we want to apply this to double‘s? Well, you let’s overload it. The implementation is largely the same. This adds code…
A default argument is a fallback value used when the caller does not provide an argument, therefore it plays the role of an optional parameter. The Premise A default argument is created using = In the example below, if the…
Due to implicit conversions, C++ allows us to call functions with arguments that don’t make sense. For example, the program below will successfully compile even though it makes no sense. The compiler doesn’t even throw an error or warning. Even…
Since C++ is a strongly-typed language, it is very pedantic. For example, the function below only operates on 2 int types. This strictness is useful but what if we want to add 2 floats? Well we can add another function,…
std::valarray is the C++ standard library’s most ambitious attempt — and most public failure — at high-performance numerics. It was added to C++98 with a specific promise: a numerical array type with aliasing rules so strict that compilers could optimise operations…
C++ programmers tend to learn the iterator hierarchy in broad strokes — input, output, forward, bidirectional, random access, in increasing order of capability — and mostly stop there. The five categories get listed in introductory material, the random-access category gets the…
Listing the files in a directory is an embarrassingly common operation that, until C++17, had no cross-platform answer in the standard library. Programs that needed it reached for POSIX’s <dirent.h> on Unix, the Win32 FindFirstFile family on Windows, and a tangle of #ifdef _WIN32 macros to…