whats wrong with this program please?

Code:

---

#include <iostream.h>
#include <windows.h>

int main()
{
        const double met=35273.92;
        double mt;
        double oz;
        double boxes;
        char go;
        int i=0;
        for(;;)
        {
                system("CLS");
            cout<<"Enter the number of ounces in your breakfast cereal: ";
            cin>>oz;
            mt=oz/met;
                for(i;i<=met;i+=oz)
                {
                        if(i>met) i-=oz;
                }
                if(met-i>0) boxes++;
                //if(met%oz>0) boxes++; this does not work for some reason
            cout<<endl<<"Your cereal is "<<mt<<" metric ton(s) and it would take "<<boxes<<" boxes to make a metric ton."<<endl<<endl;
                cout<<"Would you like to do another cereal?(y/n): ";
                cin>>go;
                if(go=='n' || go=='N') break;
        }
        return 0;
}

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include stdlib.h to support system calls
the % operator doesn't work on doubles. use fmod(a,b), and include math.h
make boxes an int