c primer plus 第十六章课后编程3题

#include <stdio.h>
#include <math.h>
#define PI 3.14159265
struct polar_coordinates {
double r;
double a;
};

struct rectangular_coordinates {
double x;
double y;
};
struct rectangular_coordinates ps(struct polar_coordinates *);

int main(void)
{
struct polar_coordinates kai ={2.3, 32.0};
struct rectangular_coordinates k;
k=ps(&kai);

printf(“x==%lf y==%lf\n”,k.x, k.y);

return 0;
}

struct rectangular_coordinates ps(struct polar_coordinates *j)
{
struct rectangular_coordinates k;
k.x = j->r * cos(j->a * (PI/180));
k.y = j->r * sin(j->a * (PI/180));

return k;
}