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YuSong4869

于 2015-06-10 19:44:57 发布

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本文链接：https://blog.youkuaiyun.com/YuSong4869/article/details/46445853

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<img src="https://img-blog.youkuaiyun.com/20150610194457571?watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvWXVTb25nNDg2OQ==/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/Center" alt="" />#include <iostream> 
#include <cmath> 
using namespace std; 
int main()  
{double a,b,c,s,area;  
cout<<"please input a,b,c:"; 
cin>>a>>b>>c;
if (a+b<=c)
cerr<<"a+b<=c,error!"<<endl; 
else if(b+c<=a)
cerr<<"b+c<=a,error!"<<endl; 
else if (c+a<=b)  
cerr<<"c+a<=b,error!"<<endl; 
else  
{s=(a+b+c)/2;  
area=sqrt(s*(s-a)*(s-b)*(s-c)); 
cout<<"area="<<area<<endl;} 
return 0; 
}