c plus template

Template

Before this , we always define a function or class to do same operations with  variables from fixed type. when type changed, we should define another function or class to do it.

Template provide a mechanism that we can only define a function to do the same works with variables from different types.

define: template <typename T>

exmple:

Funtion Template:

#include<iostream>
using namespace std;

template <typename T>
T sum(T a, T b)
{
	return a + b;
}

int main ()
{
	int a = sum(3 , 4);
	float b = sum(3.4f, 4.5f);
	
	cout << "3 + 4 = " << a << endl;
	cout << "3.4 + 4.5 = " << b << endl;

	return 0;
}

Class Template:

#include<iostream>
using namespace std;

template <typename T>
class Complex
{
	T real, imag;
public:
	Complex(T r = 0, T i = 0)
	{
		real = r;
		imag = i;
	}
	void print()
	{
		cout << real << " + " << imag << " i";
		cout << endl;
	}
};

int main()
{
	Complex<int> c1(1, 2);
	Complex<float> c2(1.2, 2.3);
	
	cout << "c1 = ";
	c1.print();
	
	cout << "c2 = ";
	c2.print();

	return 0;
}