#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main()
{
    double a,b,c;
    cout<<"please enter a,b,c:";
    cin>>a>>b>>c;
    if(a+b>c&&a+c>b&&b+c>a)
    {
        double s,area;
        s=(a+b+c)/2;
        area=sqrt(s*(s-a)*s*(s-b)*(s-c));
        cout <<setiosflags(ios::fixed)<<setprecision(4);
        cout <<"area="<<area<<endl;
    }
    else cout<<“it is not a trilateral!"<<endl;
        return 0;
}



[ 本帖最后由 ydq7113103 于 2009-11-22 19:22 编辑 ]

  cout>>a>>b>>c;//这个地方应该是cin
cout<<'it is not a trilateral!"<<endl;//这个地方你的引号错了该是"

改了之后还是运行部了啊
  谢谢你啊

#include <iostream>
#include <cmath>
#include <iomanip>
using namespace std;
int main()
{
    double a,b,c;
    cout<<"please enter a,b,c:";
    cin>>a>>b>>c;
    if(a+b>c&&a+c>b&&b+c>a)
    {
        double s,area;
        s=(a+b+c)/2;
        area=sqrt(s*(s-a)*s*(s-b)*(s-c));
        cout <<setiosflags(ios::fixed)<<setprecision(4);
        cout <<"area="<<area<<endl;
    }
    else cout<<   "    it is not a trilateral!"<<endl;
        return 0;  
}
把那个引号改了，我机子可以运行！

PS：我也是直接复制到VS2008上运行的哦！