Class template argument deduction (CTAD) C++17 Starting in C++17, when instantiating an object from a class template, the compiler can deduce the template types from the types of the object’s initializer (this is called or for short). For example: #include <utility> // for std::pair int main() { std::pair<int, int> p1{ …
In lesson , we introduced the challenge of having to create a separate (overloaded) function for each different set of types we want to work with: #include <iostream> // function to calculate the greater of two int values int max(int x, int y) { return (x > y) ? x …
In a prior lesson (), we indicated that the syntax for a function definition looks like this: return-type identifier() // identifier replaced with the name of your function { // Your code here } Although we showed examples of functions that had return-type void, we did not discuss what this …
Quick review (also called ) are data types that can be constructed from fundamental data types (or other compound data types). The of an expression indicates whether an expression resolves to a value, a function, or an object of some kind. An is an expression that evaluates to a function …
There are certain questions that tend to get asked over and over. This FAQ will attempt to answer the most common ones. Q: Why shouldn’t we use “using namespace std”? The statement using namespace std; is a . Using directives import all of the identifiers from a namespace into the …
In lesson , we introduced the constexpr keyword, which we used to create compile-time (symbolic) constants. We also introduced constant expressions, which are expressions that can be evaluated at compile-time rather than runtime. Consider the following program, which uses two constexpr variables: #include <iostream> int main() { constexpr int x{ …
The ability to generate random numbers can be useful in certain kinds of programs, particularly in games, statistical modelling programs, and cryptographic applications that need to encrypt and decrypt things. Take games for example — without random events, monsters would always attack you the same way, you’d always find the …
In lesson , we discussed how the auto keyword can be used to have the compiler deduce the type of a variable from the initializer: int getVal(); // some function that returns an int by value int main() { auto val { getVal() }; // val deduced as type int …
Consider an employee represented by 3 loose variables: int main() { int id { 1 }; int age { 24 }; double wage { 52400.0 }; return 0; } If we want to pass this employee to a function, we have to pass three variables: #include <iostream> void printEmployee(int id, …
When we define a struct (or class) type, we can provide a default initialization value for each member as part of the type definition. This process is called , and the initialization value is called a . Here’s an example: struct Something { int x; // no initialization value (bad) …
