Ebooks Chapter 5 PROBLEM SOLVING AND PROGRAM DESIGN IN C

5.5 Figure 5.9 Program To Monitor Gasoline Storage Tank

#include <cstdlib>
#include <iostream>
#define capacity 80000.0
#define min_pct 10
#define gals_per_brl 42.0

double monitor_gas(double min_supplay,double start_supply);

using namespace std;

int main(void)
{
    double start_supply, min_supply, current;
    min_supply = min_pct/100.0*capacity;
    cout<<"Numbers Of Barrels currently in tank : ";
    cin>>start_supply;
   
    current = monitor_gas(min_supply, start_supply);
    cout<<"Only Barrels are left."<<current<<endl<<endl;
    cout<<"*** WARNING ***"<<endl;
    cout<<"Available Supply is lesss than percent of"<<min_pct<<"tank's "<<endl;
    cout<<capacity<<"barrel capacity."<<endl;
   
    system("PAUSE");
    return EXIT_SUCCESS;
}

double monitor_gas(double min_supply,double start_supply)
{
       double remov_gals, remov_brls,current;
              for(current = start_supply; current >= min_supply; current -= remov_brls){
                          cout<<"Barrels are available."<<current<<endl<<endl;
                          cout<<"Enter number of gallons removed : ";
                          cin>>remov_gals;
                          remov_brls = remov_gals/gals_per_brl;
                         
                          cout<<"After removal of"<<remov_gals<<"gallone ("<<remov_brls<<"barrels)"<<endl;
                          }
                          return(current);
}
                         

c++ :