>>451
#include<stdio.h>
main()
{
double pi,r1,r2,h,V;
printf( "外径\n" );
scanf( "%lf", &r1 );
printf( "内径\n" );
scanf( "%lf", &r2 );
printf( "高さ\n" );
scanf( "%lf", &h );
pi = 3.14159265358979;
V = (pi * (r1 / 2.0) * (r1 / 2.0) + h) - (pi * (r2 / 2.0) * (r2 / 2.0) + h);
printf( "中空円筒の体積\n%f\n", V );
return 0;
}