import std.stdio, std.math, std.string;
void main() {
  writefln("This is an application to work out the reverberation time (RT60) of a rectangular room
Firstly, you will need to understand which wall is which:
1 - The wall on your left
2 - The wall in front of you
3 - The wall on your right
4 - The wall behind you
5 - The ceiling
6 - The floor");
        float readline(string label) { writef(label); return atof(readln); }
        writefln("Please enter the dimensions of the room in m");
        auto height=abs(readline("Height: "));
        auto width=abs(readline("Width: "));
        auto length=abs(readline("Length: "));
        auto volume=height*width*length;
        writefln("Now, please enter the absorption co-efficients of the surfaces in the room.
Values must be equal either 0 or 1, or lie between them. If the value entered does not, you will be asked to enter again.");
        float[string] walls=[
          "Left"[]: height*length, "Right": height*length,
          "Roof": width*length, "Floor": width*length,
          "Front": width*height, "Back": width*height
        ];
        float a=0;
        foreach (name, area; walls) {
          float ain;
          do ain=readline(name~": ");
          while (ain<0 || ain>1);
          a += ain*area;
        }
        // Now that we have all the variables needed, we can work out the reverberation time, using the sabine equation.
        float reverberationtime = (0.161*volume)/a;
        
        writefln("The reverberation time of this room is ", reverberationtime, " seconds.");
}