例31: # include≤ iostream. h> #define pi 3.1415926 void maino const float h=5.0 int r=7.0.v: 次次 cout<<y<<endl例3.1： #include <iostream.h> #define pi 3.1415926 void main() { const float H=5.0; int r=7.0,v; v=pi*r*r*H; cout<<v<<endl; }