shape.h

易学c++源码

//*****************
//*    shape.h    *
//*****************
#include "math.h"
const double pi=3.14159265358;
struct circle
{
	double r;
};
struct square
{
	double a;
};
struct rectangle
{
	double a,b;
};
struct triangle
{
	double a,b,c,alpha,beta,gamma;
};
double perimeter_of_circle(double r)
{
	return 2*pi*r;
}
double area_of_circle(double r)
{
	return pi*r*r;
}
double perimeter_of_square(double a)
{
	return 4*a;
}
double area_of_square(double a)
{
	return a*a;
}
double perimeter_of_rectangle(double a,double b)
{
	return 2*(a+b);
}
double area_of_rectangle(double a,double b)
{
	return a*b;
}
double perimeter_of_triangle(double a,double b,double c)
{
	return a+b+c;
}
double area_of_triangle(double a,double b,double gamma)
{
	return sin(gamma/180*pi)*a*b/2;
}