C++ Exercise

[matthew8810]

Hi everyone, I am in the fourth year of high school and I'm working on a program in C ++, which mixes the electrical circuits of physics with C ++. the delivery involves the creation of a program in C ++, in which the resistance and the capacitor must be inserted in two separate classes with their own attributes, methods and constructors. also in the main it is indicated to insert 3 resistors and 2 capacitors. I leave you both the original delivery and my work. "Create a program that allows the insertion of two bipoles (Resistance and Capacitor) through two non-derived classes by implementing the manufacturers the attributes and the get and set methods for each attribute. Create a main that allows you to insert 3 resistors and 2 capacitors"
at the moment I'm only working with the class of capacitors, to concentrate on the code of it

#include <iostream>
#include <cmath> 
using namespace std;
class capacitors{
	public:
		double Formula();
		void GetCapacitors();
		void SetCapacitors();
		double Parallel();
		double Series();
	private:
		double AccumulatedCharge;
		double PotentialDifference; 
};
double capacitors::Formula(){
	return (abs(capacitors::AccumulatedCharge)/abs(capacitors::PotentialDifference));
}
void capacitors::SetCapacitors(){
	double charge, difference;
	cout<<"\nQ:";cin>>charge;
	do { cout<<"\nV: ";cin>>difference;
	} while(difference==0);
	AccumulatedCharge=charge;
	PotentialDifference=difference;
}
void capacitors::GetCapacitors(){
	cout <<"\nQ= "<< abs(AccumulatedCharge);
	cout <<"\nV= "<< abs(PotentialDifference);
	cout <<"\n----------------";
}

main(){
    for(int i=0; i<3;i++){
    	capacitors C;
    		cout<<"\nInsert Value:";
    		C.SetCapacitors();
    		cout<<"\nThe following values have been entered:";
    		C.GetCapacitors();
    		cout<<"\nThe capacity of the capacitors is equal to: "<<C.Formula()<<"\b F.";
   }
}

for the insertion of the 3 capacitors, through a FOR loop I can only get them displayed, but in case I want to make each value of the capacitors interact, for example the capacity of the capacitor 1 + capacitor2 + capacitor3, as I do, since they are values entered at the moment and printed?

[TheToaster]

Can you rephrase your question?

[Ganado]

I don't get the purpose of your "Capacitors" class.
Is your capacitors class supposed to represent a single capacitor or multiple capacitors? It sounds like the latter. But the rest of your code doesn't really allow this.

I think you're getting bogged down by the verbosity of your class functionality.

If you want to tell the user to enter a capacitors, say, in parallel, then you need to enter 1 voltage, and then N charges.
If you want to compute the total capacitance, then you need to sum the charges, then divide by the voltage.

[matthew8810]

to tell you the truth I'm really confused 🥺, What I wanted to do was a class that represents a single capacitor and then through an Array, insert 2 of them. And then do the same with the resistance class.

What would you have done for me?
I have a lot of ideas in my head, but they get confused between them🤦🏻‍♂️

[Ganado]

Okay, something like,

#include <iostream>

class Capacitor {
  public: // simplified for brevity
    double charge; 
    double voltage;
};

int main()
{
    using namespace std;

    Capacitor caps[3]; // array of 3 capacitors
    cout << "Enter voltage across the 3 capacitors in parallel: ";
    double voltage;
    cin >> voltage;

    for (int i = 0; i < 3; i++)
    {
        // ask user to enter attributes of capacitor
        cout << "Enter charge of capacitor " << i << ": ";
        cin >> caps[i].charge;
        caps[i].voltage = voltage; // already known
    }

    double total_charge = 0;
    for (int i = 0; i < 3; i++)
    {
        total_charge += caps[i].charge;
    }

    cout << "C = " << total_charge / voltage;
}

Enter voltage across the 3 capacitors in parallel: 120
Enter charge of capacitor 0: 30
Enter charge of capacitor 1: 30
Enter charge of capacitor 2: 30
C = 0.75 F

[matthew8810]

in the for loop

// e.g.

what means e.g?
in this case how i can implement set and get method in the for loop?

[Ganado]

I dunno, if you want to add getter/setter boilerplate, feel free to do so.
Something like:

class Capacitor {
  public:
    double getVoltage()
    {
        return voltage;
    }
    void setVoltage(double voltage)
    {
        this->voltage = voltage;
    }

    double getCharge()
    {
        return charge;
    }
    void setCharge(double charge)
    {
        this->charge = charge;
    }

    double getCapacitance()
    {
        // Q = CV
        return charge / voltage;
    }
  private:
    double voltage;
    double charge;
};

I also edited my previous post with a bit more detail.

[matthew8810]

please can you explain me what you have done here?

class Capacitor {
  public:
    double getVoltage()
    {
        return voltage;
    }
    void setVoltage(double voltage)
    {
        this->voltage = voltage;
    }

    double getCharge()
    {
        return charge;
    }
    void setCharge(double charge)
    {
        this->charge = charge;
    }

    double getCapacitance()
    {
        // Q = CV
        return charge / voltage;
    }
  private:
    double voltage;
    double charge;
};

[Ganado]

It's just setters/getters for things you might want from a capacitor (voltage, charge, calculating the capacitance).

I suggest looking at a tutorial on classes if this doesn't make sense.
http://www.cplusplus.com/doc/tutorial/
http://www.cplusplus.com/doc/tutorial/classes/

[matthew8810]

thank you very much, now I read and then I try to do it again, if I have new problems I will rewrite

[matthew8810]

#include <iostream>
using namespace std;
class capacitator{
	public:
		double GetCharge(){
				return charge;
		};
		void SetCharge(){
			cout<<"Charge: "; cin>>charge;
		};
		double GetVoltage(){
			return voltage;
		};
		void SetVoltage(){
			cout<<"Voltage: "; cin>>voltage;
		};
		double GetCapacity(){
			return charge/voltage;
		};
		double charge;
		double voltage;
};

main(){
double voltage;
	capacitator c[2];
    		cout<<"\nEnter voltage:";    	
    		cin>>voltage;
		    for(int i=0; i<3;i++){
				cout<<"\nEnter charge of capacitator"<<i<<": ";
      		  	cin>>c[i].charge;
      		 	c[i].voltage=voltage;
    double TotalCharge=0;
    	for (int i=0; i<3; i++){
       	 	TotalCharge += c[i].GetCharge();
   		}

    cout<<"\nC="<<TotalCharge/voltage;
   }

}

I managed to set it this way here, correct?

[Ganado]

Perché hai iniziato a parlare italiano? :)

è corretto

No.

A few issues:
1. The signature of your main function should be int main(), not just main().

2. On line 26, you declare an array of size 2, but you loop over 3 elements. Make your array size be 3 instead of 2.

3. It sounds like you're supposed to use getters/setters, but you don't use your setters. The way you have it isn't wrong, but it's peculiar. You never use your SetCharge or SetVoltage functions.

Other than that... it looks okay.

[matthew8810]

Perché hai iniziato a parlare italiano? :)

because I am Italian, here the forums are not very good, so I preferred to focus on the American ones 😅

2.

I remember that with Arrays "formula" N-1 was used in the Array dimension because they start from 0, in any case, I will fix it.

3.

How should I use them? in case of SetVoltage I should insert it on line 27/28?
And SetCharge on line 31? "c[i].SetCharge"?

[Ganado]

When you declare an array, the number itself is the size of the array.

int arr[5]; allocates 5 ints.
The tricky part is that the first index is 0. So it's 5 ints, but the indices are 0, 1, 2, 3, 4.
That's where the "N-1" thing comes from.

In your SetX functions, you force the user to input data.
Instead, you should do something more like

double charge;
cin >> charge;
c[i].SetCharge(charge); // each capacitor has a different charge

c[i].SetVoltage(voltage); // each capacitor has the same voltage (in parallel) 

And in your class, SetCharge can look like:

void SetCharge(double charge)
{
    this->charge = charge;
}
void SetVoltage(double voltage)
{
    this->voltage = voltage;
}

[matthew8810]

Ok thanks, i've settled all. for resistances, I should work in a similar way right?

[dhayden]

The charge and voltage across a capacitor are functions of the circuit that they are in, not the capacitor itself. So I would store the capacitance in the Capacitor class.

Similarly, I'd store the resistance in the Resistor class.

Create a main that allows you to insert 3 resistors and 2 capacitors"

Should they be inserted in a fixed configuration? Or can the user insert them in any combination of series & parallel?

What should be the output of the program? Total capacitance? Resistance? Impedance?

[Ganado]

The charge and voltage across a capacitor are functions of the circuit that they are in, not the capacitor itself. So I would store the capacitance in the Capacitor class.

Heh true that makes a lot more sense, actually. I guess I was just trying to go off of the class OP had already established (sort of).

[matthew8810]

so the operation that should be done is to move the part of the total capacity, inside a function of the capacitor class, right?

Should they be inserted in a fixed configuration? Or can the user insert them in any combination of series & parallel?

it is not specified, but I continue with a parallel circuit, the ideal would be to make the user decide which circuit they are in, but I see it as too complex for my knowledge😅

What should be the output of the program? Total capacitance? Resistance? Impedance?

That's right, those are the output data, momentarily I only have that of the capacitor, but I will add the others.

EDIT:
a friend told me that I should put instead of C = Q / V, Q = C * V, so in case you want to insert 1microFarad there is no need to calculate it by hand, is worth?