Lecture 3

We will look at passing multiple template parameters in our template parameter list. Have a look at the code:

	#include<iostream>
	template<typename t1, typename t2>
	void foo(t1 input1, t2 input2)
	{
	std::cout<<input1<<std::endl;
	std::cout<<input2<<std::endl;

	}
	int main()
	{
	   foo<int, float>(3, 4.5f);
	   return 0;
	}

We shall copy this code in https://cppinsights.io/ and have a look at what kind of code compiler generates on our behalf if we use templates. Following are insights from above webpage:

			#include<iostream>
			template<typename t1, typename t2>
		void foo(t1 input1, t2 input2)
		{
		  (std::cout << input1) << std::endl;
		  (std::cout << input2) << std::endl;
		}

			
			/* First instantiated from: insights.cpp:12 */
			#ifdef INSIGHTS_USE_TEMPLATE
			template<>
			void foo<int, float>(int input1, float input2)
			{
			  std::cout.operator<<(input1).operator<<(std::endl);
			  std::cout.operator<<(input2).operator<<(std::endl);
			}
			#endif
			
			int main()
		 {
		   foo<int, float>(3, 4.5F);
		   return 0;
		 }

To print the type names we can include <typeinfo>

	#include<iostream>
	#include<typeinfo>
	template<typename t1, typename t2>
	void foo(t1 input1, t2 input2)
	{
	std::cout<<typeid(input1).name()<<std::endl;
	std::cout<<typeid(input2).name()<<std::endl;
	}
	int main()
	{
	   foo<int, float>(3, 4.5f);
	   foo<float,int>(3.4f, 6); //this will create two instantiatons of templates.
	   return 0;
	}

Multiple template parameters and and non-object type parameters: