类和对象问题

#include<iostream>
using namespace std;
class triangle
{public:
triangle(int,int,int);
int c();
int s();
void set();
void show();
private:
int x,y,z;
};
int triangle::c()
{return(x+y+z);
}
int triangle::s()
{return(x*y*z);
}
void triangle::set()
{cin>>x>>y>>z;
}
void triangle::show()
{cout<<x<<y<<z<<endl;
}
int main()
{triangle T;
cout<<"请输入三角形的三边长"<<endl;
T.set();
cout<<"三角形的周长为："<<T.c()<<endl;
cout<<"三角形的面积为："<<T.s()<<endl;
cout<<"三角形的长度值为："<<endl;
T.show();
return 0;
}

这是修改后的程序，但是运行不了#include<iostream>#include<cmath>using namespace std;class triangle{public:triangle();double c();double s();void set();void show();private:double x;double y;double z;};double triangle::c(){return(x+y+z);}double triangle::s(){double S,q;q=(x+y+z)/2;S=sqrt(q*(q-x)*(q-y)*(q-z));return (S);}void triangle::set(){cin>>x;cin>>y;cin>>z;}void triangle::show(){cout<<x<<y<<z<<endl;}int main(){triangle T;double x,y,z;cout<<"请输入三角形的三边长"<<endl;T.set();if(x+y>z&&y+z>x&&x+z>y){cout<<"三角形的周长为："<<T.c()<<endl;cout<<"三角形的面积为："<<T.s()<<endl;cout<<"三角形的长度值为："<<endl;T.show();}else cout<<"it is not a triangle."<<endl;return 0;}