如有失误之处,还恳请指教!!!
// strctfun.cpp -- functions with a structure argument
#include <iostream>
#include <cmath>
// structure declarations
//结构声明
struct polar
{
double distance; // distance from origin
double angle; // direction from origin
};
struct rect
{
double x; // horizontal distance from origin
double y; // vertical distance from origin
};
// prototypes
//函数原型:返回值为自定义类型polar类型,含有一个参数,参数类型为自定义rect类型
polar rect_to_polar(rect xypos);
//函数原型:没有返回值,含有一个参数,参数类型为自定义polar类型
void show_polar(polar dapos);
int main()
{
using namespace std;
//声明自定义类型rect和polar类型的变量
rect rplace;
polar pplace;
cout << "Enter the x and y values: ";
//这里使用的依然是将cin作为判断条件
while (cin >> rplace.x >> rplace.y) // slick use of cin
{
//调用rect_to_polar()函数并将rplace作为实际参数传递,将rect_to_polar的返回值赋值给
//自定义类型变量
pplace = rect_to_polar(rplace);
show_polar(pplace);
cout << "Next two numbers (q to quit): ";
}
cout << "Done.\n";
return 0;
}
// convert rectangular to polar coordinates
polar rect_to_polar(rect xypos)
{
using namespace std;
polar answer;
answer.distance =
sqrt( xypos.x * xypos.x + xypos.y * xypos.y);
answer.angle = atan2(xypos.y, xypos.x);
return answer; // returns a polar structure
}
// show polar coordinates, converting angle to degrees
void show_polar (polar dapos)
{
using namespace std;
const double Rad_to_deg = 57.29577951;
cout << "distance = " << dapos.distance;
cout << ", angle = " << dapos.angle * Rad_to_deg;
cout << " degrees\n";
}