ex4_3.cpp

纯粹是学习专用～

#include<iostream.h>
#include<math.h>
float TriangleArea(float a, float b, float c){
	if ((a+b<=c)||(a+c<=b)||(b+c<=a)) return -1;
	float s;
	s=(a+b+c)/2;
	return sqrt(s*(s-a)*(s-b)*(s-c));
}
void main(){
	float a,b,c,area;
	cout<<"输入三角形三边a,b,c:"<<endl;
	cin>>a>>b>>c;
	area=TriangleArea(a,b,c);
	if(area==-1)
		cout<<'('<<a<<','<<b<<','<<c<<')'<<"不能构成三角形！"<<endl;
	else
		cout<<"三角形("<<a<<','<<b<<','<<c<<")面积为："<<area<<endl;
}