#include <iostream>
#include <fstream>
#include <cmath>
using namespace std;
const double PI = 3.141593;

int main()
{
	//declare data items
	double t, f;
	ofstream dsine;
    
	//generate date file
	dsine.open("dsine.dat");
	for (int i = 1; i <= 100; i++)
	{
		t = 0.1*(i-1);
		f = exp(-t)*sin(2*PI*t);
		cout << t << " " << f << endl;
		dsine << t << " " << f << endl;
	}
		
	//close the data file and exit
	dsine.close();
	return 0;
	}