#include <iostream>
#include <cmath>
#include <cstdlib>
using namespace std;
typedef struct Pipe {
     double diameter ; // [mm]
     double length ;  // [m]
     double thickness ; // [mm]
     char *material ;   // "Cast iron" "Steel"  "Cu" "PVC" "Al"
} PIPE;      // ---------------------------------
void display_pipe(PIPE pipe0 );
void create_pipe(PIPE *pipe0);
int main() // How to use  STRUCTURES !!!! -------------------
{   const int SIZE=1000;
    PIPE  pipes[SIZE];
    for (int i=0; i<SIZE; i++){
        create_pipe(&pipes[i]);
        display_pipe(pipes[i]);
    }



    return 0;
} // --------------------------------------
double pipe_volume(PIPE pipe0){
    double vol, s1, s2;
    s1 = M_PI*pow(pipe0.diameter,2)/4;
    s2 = M_PI*pow(pipe0.diameter-2*pipe0.thickness,2)/4;
    return vol=(s1-s2)*pipe0.length/1000000;
}
double pipe_mass(PIPE pipe0){
    double mass, density=1000;
    if(pipe0.material="Steel") density=7800;
    if(pipe0.material="Cast iron") density=7800;
    if(pipe0.material="Al") density=2700;
    if(pipe0.material="PVC") density=3200;
    if(pipe0.material="Cu") density=8900;
return mass= density*pipe_volume(pipe0);
}
void create_pipe(PIPE *pipe0){
   pipe0->length = (rand()%61+10)/10.+1.;   // 1.-7. [m]
   pipe0->diameter = rand()%(5+1)*10;
   pipe0->thickness = pipe0->diameter*0.1;
   int a = rand()%5 + 1;     // 1 - 5
   if (a== 1) pipe0->material = "Steel";
   if (a== 2) pipe0->material = "Cu";
   if (a== 3) pipe0->material = "Cast Iron";
   if (a== 4) pipe0->material = "PVC";
   if (a== 5) pipe0->material = "Al";
} // -------------------------------------------------
void display_pipe(PIPE pipe0 ){
    cout <<"Pipe parameters"<<endl;
    cout << " diameter  " <<pipe0.diameter<< endl;
    cout << " length  " <<pipe0.length<< endl;
    cout << " thickness   " <<pipe0.thickness<< endl;
    cout << " material  " <<pipe0.material << endl;
    cout << " mass  " <<pipe_mass(pipe0) <<" kg "<< endl;
    cout << endl;
} // ----------------------------------------------