C++

Type Inference, when initializing a variable, the auto keyword can be used in place of the variable type to tell the compiler to infer the variable's type from the initializer's type
The auto keyword can't be used with function parameters

#include <iostream>
#include <vector>
#include <typeinfo>
 
//std::vector<int> getContainer()
auto getContainer() -> std::vector<int>//C++11, trailing return type syntax
//auto getContainer()//C++14
{
	std::vector<int> c = {1, 2, 3, 4};
 
	return c;
}
 
int main(int argc, char *argv[])
{
	auto i = 10;
	std::cout<<typeid(i).name()<<std::endl;
 
	auto d = 3.14;
	std::cout<<typeid(d).name()<<std::endl;
 
	auto c = getContainer();
	std::cout<<typeid(c).name()<<std::endl;
	for(int i = 0; i < c.size(); i++)
		std::cout<<c[i]<<" ";
	std::cout<<std::endl;
 
	return 0;
}

//g++ main.cpp -std=c++14
#include <iostream>
#include <initializer_list>
#include <typeinfo>
 
template <class T, class T2>
auto getProduct(T a, T2 b) -> decltype(a*b)//C++11, trailing return type syntax
auto getProduct(T a, T2 b)//C++14
{
	auto p = a*b;
	std::cout<<"Type: "<<typeid(p).name()<<std::endl;
 
	return p;
}
 
int main(int argc, char *argv[])
{
	int a = 1;
	double b = 10.0;
 
	std::cout<<getProduct(1, 4)<<std::endl;
 
	return 0;
}

decltype provides a standardized version of typeof

#include <iostream>
#include <typeinfo>
 
int main(int argc, char *argv[])
{
	int a = 10;
	decltype(a) y;
 
	std::cout<<typeid(y).name()<<std::endl;
 
	return 0;
}