C++ Auto

  • The auto keyword is a C++11 feature. 
  • Note:- Use “g++ -std=c++0x filename.cpp” to enable this feature.
  • The compiler is able to determine the type of a variable from its initialization.
  • With the advent of template types and template metaprogramming techniques, the type of something, particularly the well-defined return value of a function, may not be easily expressed. C++11 auto keyword provides a mitigation for this.
  • auto is also useful for reducing the verbosity of the code.

    Demonstrate the usage of “auto” keyword

    #include <iostream>#include <map>using namespace std;int main() {auto x = 100; // type of x is intmap<int, string> employees;employees[100] = "John";map<int, string>::iterator iter1 = employees.begin(); // More verbose, prior to C++ 11auto iter2 = employees.begin(); // In C++ 11 using autoreturn 0;}