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Result not as expected-- classes, getters, setters and switch.

ROCKRIDER50 (7)
Hi,
I'm learning C++. I am trying to write a program to calculate the total surface area and volume of cuboids, spheres, cones and cylinders. The program is giving unexpected outputs mostly random numbers with exponents of minus a few hundreds. What am I doing wrong here? P.S: I will only be able to follow up 12 hours from posting. Don't expect a reply
before 7:30 GMT).
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#include <iostream>
#include <cmath>
using namespace std;
class calcformulae
{
    private:

        //vars--------------------------------------------------------------------

        double vc,vs,vco,vcy,sac,sas,saco,sacy,l,b,h,ll,bb,hh,r,rr,rrr,rd,hhh,hd,rco,rcc,hco,hcc;

        //eqns--------------------------------------------------------------------

        void cuboidv(){vc=l*b*h;}
        void cuboidsa(){sac=2*hh*(ll+bb);}

        void spherev(){vs=(4/3)*(22/7)*r*r*r;}
        void spheresa(){sas=4*(22/7)*rr*rr;}

        void cylinderv(){vcy=(22/7)*rrr*rrr*hhh;}
        void cylindersa(){sacy=2*(22/7)*rd*(rd+hd);}

        void conev(){vco=(1/3)*(22/7)*rco*rco*hco;}
        void conesa(){saco=(22/7)*rcc*(rcc+sqrt(rcc*rcc+hcc*hcc));}

    public:

        //setters-------------------------------------------------------------------------

        void setCuboidv(double x,double y,double z){l=x;b=y;h=z;}
        void setCuboidsa(double xx,double yy,double zz){ll=xx;bb=yy;hh=zz;}

        void setSpherev(double w){r=w;}
        void setSpheresa(double ww){rr=ww;}

        void setCylinderv(double www,double zzz){rrr=www;hhh=zzz;}
        void setCylindersa(double wd,double zd){rd=wd;hd=zd;}

        void setConev(double wco,double zco){rco=wco;hco=zco;}
        void setConesa(double wcc,double zcc){rcc=wcc;hcc=zcc;}

        //getters--------------------------------------------------------------------------

        double getCuboidv(){return vc;}
        double getCuboidsa(){return sac;}
        double getSpherev(){return vs;}
        double getSpheresa(){return sas;}
        double getCylinderv(){return vcy;}
        double getCylindersa(){return sacy;}
        double getConev(){return vco;}
        double getConesa(){return saco;}
};

//implementation code----------------------------------------------------------------------

int main()
{
    calcformulae cf;
    cout<<"\nVOLUME, SURFACE AREA CALCULATOR";
    cout<<"\n-------------------------------\n\n";
    cout<<"Calculate:\n\n1)Volume \nOR\n2)Surface area?\n\n";

    int selector,shapeselector;
    double i,o,p;
    cin>>selector;

    switch(selector)
    {   case 1: case 2:
        cout<<"\nOf:\n\n1)Cuboid\n2)Sphere\n3)Cylinder\nOR\n4)Cone?\n\n";
        cin>>shapeselector;

        switch(shapeselector)
        {
            case 1:

            cout<<"\nEnter length:\n\n";
            cin>>i;

            cout<<"\nEnter width:\n\n";
            cin>>o;

            cout<<"\nEnter height:\n\n";
            cin>>p;

            switch(selector)
            {
                case 1: cf.setCuboidv(i,o,p);  cout<<endl<<cf.getCuboidv();  break;
                case 2: cf.getCuboidsa(); cout<<endl<<cf.getCuboidsa(); break;
            }
            break;

            case 2:

            cout<<"\nEnter radius:\n\n";
            cin>>i;

            switch(selector)
            {
                case 1: cf.setSpherev(i); cout<<endl<<cf.getSpherev(); break;
                case 2: cf.setSpheresa(i); cout<<endl<<cf.getSpheresa(); break;
            }
            break;

            case 3: case 4:

            cout<<"\nEnter radius:\n\n:";
            cin>>i;

            cout<<"\nEnter height:\n\n:";
            cin>>o;

            switch(shapeselector)
            {
            case 3:

                switch(selector)
                {
                    case 1: cf.setCylinderv(i,o); cout<<endl<<cf.getCylinderv(); break;
                    case 2: cf.setCylindersa(i,o); cout<<endl<<cf.getCylindersa(); break;
                }
            break;

            case 4:

                switch(selector)
                {
                    case 1: cf.setConev(i,o); cout<<endl<<cf.getConev(); break;
                    case 2: cf.setConesa(i,o); cout<<endl<<cf.getConesa(); break;
                }
            break;
            }
            default: cout<<"\nERROR\n\n\n";
            main();
        }

        default: cout<<"\nERROR\n\n\n";main();
    }


return 0;
}
Last edited on
MiiNiPaa (8886)
You never call cuboidv(), cuboidsa(), etc. functions, so vc, sac, etc. values never initialized and contain garbage.
megatron 0 (471)
Whoa, whoa WHOA! Easy there buddy!


Have you heard of a phrase called "Containment" or Encapsulation?

What it means is that an object has certain properties that only that object has which other objects don't need to see.

For example a Cuboid doesn't have a Radius but they are both a 3DShape. Does that make sense?

Your class contains several "Properties" or Traits which should be encapsulated into it's own objects.

For example

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class Cuboid
{
private:
       double Length, Width, Height;
public:
        Cuboid(double l, double w, double h): Width(w), Length(l), Height(h) {} // Sets the variables
        double GetSurfaceArea() { return (Width*Length)*6; } // Area of a square multiplied by the amount of faces
}


All the data for a cuboid is contained within the Cuboid class. Keeping your objects simple and well defined, also allowing for better maintenance when wanting to add other features.

You have a lot of switch() statements in your code, the way you have it mapped out too is rather hard to follow.

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int main()
{
    while(1) // Keep it running until close is selected
    {
        std::cout << "Choose which object: /* List objects */ \t Or press 0 to quit: ";
        int choice;
        std::cin >> choice;
        switch(choice)
        {
        case 0: return 0; // Exit out of main
        case 1: DoCuboidStuff(); break;
        /* Do other cases */
        default: std::cout << "No such choice!\n";
        }
    }
}

void DoCuboidStuff()
{
       std::cout << "What are the dimensions(Length, Width, Height)?\n";
       double l,w,h;
       std::cin >> l >> w >> h;
       Cuboid ACuboid(l,w,h); // create a cuboid shape
       std::cout << "What calculation would you like? 1) Surface Area\t2) Volume : ";
       int choice; std::cin >> choice;
      switch(choice)
      {
      case 1: std::cout << ACuboid.GetSurfaceArea() << "\n"; break;
      /* Other calculations */
      }
}


As you can see the contained variables and functions have improved the readability of the program a lot, allowing you to see problems more easily within your own code, and allowing other programmers to spot bugs. :-)
anup30 (968)
i have corrected for 1)volume 1)Cuboid. two more break were needed in switch-case. line 88 need argument. line 14 was not called - merge it with line 44.
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#include <iostream>
#include <cmath>
using namespace std;
class calcformulae
{
    private:

        //vars--------------------------------------------------------------------

        double vc,vs,vco,vcy,sac,sas,saco,sacy,l,b,h,ll,bb,hh,r,rr,rrr,rd,hhh,hd,rco,rcc,hco,hcc;

        //eqns--------------------------------------------------------------------

        void cuboidv(){vc=l*b*h;}
        void cuboidsa(){sac=2*hh*(ll+bb);}

        void spherev(){vs=(4/3)*(22/7)*r*r*r;}
        void spheresa(){sas=4*(22/7)*rr*rr;}

        void cylinderv(){vcy=(22/7)*rrr*rrr*hhh;}
        void cylindersa(){sacy=2*(22/7)*rd*(rd+hd);}

        void conev(){vco=(1/3)*(22/7)*rco*rco*hco;}
        void conesa(){saco=(22/7)*rcc*(rcc+sqrt(rcc*rcc+hcc*hcc));}

    public:

        //setters-------------------------------------------------------------------------

        void setCuboidv(double x,double y,double z){l=x;b=y;h=z;}
        void setCuboidsa(double xx,double yy,double zz){ll=xx;bb=yy;hh=zz;}

        void setSpherev(double w){r=w;}
        void setSpheresa(double ww){rr=ww;}

        void setCylinderv(double www,double zzz){rrr=www;hhh=zzz;}
        void setCylindersa(double wd,double zd){rd=wd;hd=zd;}

        void setConev(double wco,double zco){rco=wco;hco=zco;}
        void setConesa(double wcc,double zcc){rcc=wcc;hcc=zcc;}

        //getters--------------------------------------------------------------------------

        double getCuboidv(){vc=l*b*h; return vc;} //////////////////////////////
        double getCuboidsa(){return sac;}
        double getSpherev(){return vs;}
        double getSpheresa(){return sas;}
        double getCylinderv(){return vcy;}
        double getCylindersa(){return sacy;}
        double getConev(){return vco;}
        double getConesa(){return saco;}
};

//implementation code----------------------------------------------------------------------

int main()
{
    calcformulae cf;
    cout<<"\nVOLUME, SURFACE AREA CALCULATOR";
    cout<<"\n-------------------------------\n\n";
    cout<<"Calculate:\n\n1)Volume \nOR\n2)Surface area?\n\n";

    int selector,shapeselector;
    double i,o,p;
    cin>>selector;

    switch(selector)
    {   case 1: case 2:
        cout<<"\nOf:\n\n1)Cuboid\n2)Sphere\n3)Cylinder\nOR\n4)Cone?\n\n";
        cin>>shapeselector;

        switch(shapeselector)
        {
            case 1:

            cout<<"\nEnter length:\n\n";
            cin>>i;

            cout<<"\nEnter width:\n\n";
            cin>>o;

            cout<<"\nEnter height:\n\n";
            cin>>p;

            switch(selector)
            {
                case 1: cf.setCuboidv(i,o,p);  cout<<endl<<cf.getCuboidv();  break;
                case 2: cf.getCuboidsa(); cout<<endl<<cf.getCuboidsa(); break; /////////////////////
            }
            break;

            case 2:

            cout<<"\nEnter radius:\n\n";
            cin>>i;

            switch(selector)
            {
                case 1: cf.setSpherev(i); cout<<endl<<cf.getSpherev(); break;
                case 2: cf.setSpheresa(i); cout<<endl<<cf.getSpheresa(); break;
            }
            break;

            case 3: case 4:

            cout<<"\nEnter radius:\n\n:";
            cin>>i;

            cout<<"\nEnter height:\n\n:";
            cin>>o;

            switch(shapeselector)
            {
            case 3:

                switch(selector)
                {
                    case 1: cf.setCylinderv(i,o); cout<<endl<<cf.getCylinderv(); break;
                    case 2: cf.setCylindersa(i,o); cout<<endl<<cf.getCylindersa(); break;
                }
            break;

            case 4:

                switch(selector)
                {
                    case 1: cf.setConev(i,o); cout<<endl<<cf.getConev(); break;
                    case 2: cf.setConesa(i,o); cout<<endl<<cf.getConesa(); break;
                }
            break;
            } break; ////////////////////////////
            default: cout<<"\nERROR\n\n\n";
            main();//////////////////////// use goto
        }
        break; ///////////////////////////
        default: cout<<"\nERROR\n\n\n";main();/////////// use goto
    }


return 0;
}
Last edited on
ROCKRIDER50 (7)
Thanks for the advice everybody. Just to be clear, here is my interpretation of all your answers:

1)Too many nested switches making stuff complex-- simplify.
2)Encapsulate different shapes in different classes.
3)Fix goof-ups (like line 88).

Thanks for the help.
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