7iv.cpp

《C/C＋＋程序设计导论（第二版）》一书的程序源文件

// drawcos.cpp  Plot the cosine function horizontally on the
//   screen for angles from 0 to 3p.
#include <iostream.h>
#include <math.h>
// PlotPoint ()  Plot the cosine of the angle parameter
// on a line across the screen
//   IN:  angle -- the angle in radians to be plotted
void PlotPoint (float angle)
{	int blanks, position;
	position = cos (angle) * 35 + 35;
	for (blanks=0; blanks<position; blanks=blanks+1)
		cout << " ";
	cout << "*" << endl;
}
// PlotYAxis()  draw a Y axis and fiducial marks on screen
void PlotYAxis()
{	cout << " -1.0                               0.0                             1.0" << endl;
	cout << "--------------------------|----------------------" << endl;
}
void main ()
{	float angle;
	const float anglestep = 0.1885;					// 3p / 50
	const float limit = 9.42478;					// 3p
	PlotYAxis();					// draw the Y axis
// plot a point for each angle from 0 to 3p in steps of 3p/50
	for (angle=0.0; angle<limit; angle=angle+anglestep)
		PlotPoint (angle);
}