代碼以下:ios
1 #include <iostream> 2 #include <iomanip> 3 using namespace std; 4 int main() 5 { 6 double d=0.3,pi=3.14,s; 7 s=2*pi*(d/2)*(d/2); 8 cout<<fixed<<setprecision(5)<<s<<endl; 9 return 0; 10 }