C++17 STL Cookbook

How to do it...

Variables are initialized in one step. Using the initializer syntax, there are two different situations:

• Using the brace initializer syntax without auto type deduction:

       // Three identical ways to initialize an int:       int x1 = 1;       int x2  {1};       int x3  (1);              std::vector<int> v1   {1, 2, 3}; // Vector with three ints: 1, 2, 3       std::vector<int> v2 = {1, 2, 3}; // same here       std::vector<int> v3   (10, 20);  // Vector with 10 ints,                                         // each have value 20

• Using the brace initializer syntax with auto type deduction:

       auto v   {1};         // v is int       auto w   {1, 2};      // error: only single elements in direct                              // auto initialization allowed! (this is new)       auto x = {1};         // x is std::initializer_list<int> auto y = {1, 2}; // y is std::initializer_list<int> ...