C++ Help with force calculator

[Herman09851]

Hi, I am a newbie to c++ and for college, I need to make a force calculator. I have done this so far but it won't calculate the Fx and Fy when I run it like this.
Does anybody know what I am doing wrong? ps. I need to use a void function in my code and I'm dutch that's why there are some lines in dutch in the code 🙂

using namespace std;
double Force = 1.0, Angle, AmountF, Quadrant, Fx, Fy;

void checkkwadrant()
{
    if (Quadrant == 2) {
        //Quadrant 2 dus ten op zichte van xas in Quadrant 1 is een AmountF in Quadrant twee 180 - hoek weg van de x-as in Quadrant 1
        Angle = 180 - Angle;
        Force == -Force;
        
    }

    else if (Quadrant == 3) {
        Angle = 180 + Angle;
        Force == -Force;
        
    }

    else if (Quadrant == 4) {
        Angle = 360 - Angle;
        Force == -Force;
        
    }

    else if (Quadrant != 1 && Quadrant != 2 && Quadrant != 3 && Quadrant != 4)
    {
        //stap 5
        cout << "Kwadrant " << Quadrant << " bestaat niet " << endl;
        cout << "Vul een bestaande waarde in! ";
        cout << "" << endl;
        Fx = 0;
        Fy = 0;
    }

    Fx = Force * cos(Angle);
    Fy = Force * sin(Angle);
}

int main()
{

    double Fx = 0.0, Fy = 0.0;
    //stap 1:
    cout << "Geef aantal krachten die berekend moeten worden: ";
    //stap 2
    cin >> AmountF;
    cout << "" << endl;
    //stap 3
    cout << "Voer grootte in (zonder eenheid), hoek (in graden, vanaf x-as) en richting (welk Quadrant) in van elke vector." << endl;

    for (int i = 0; i < AmountF; i++) {
        //stap 4

        cin >> Force;
        cin >> Angle;
        cin >> Quadrant;

        //stap 6
        //6a
        Angle *= 3.14159 / 180;

        //6b
        checkkwadrant();

        //6c
        cout << "Fx = " << Fx << " en Fy = " << Fy << endl;
    }

    //Force = sqrt(Fx * Fx + Fy * Fy);
    //Angle = atan2(Fy, Fx) * 180.0 / 3.14159;

    cout << "Het resultant van de vector heeft een grootte: " << Force << " met een hoek van: " << Angle << " graden vanaf de x-as " << endl;

}

 

[BGB]

You are declaring the Fx and Fy twice. Remove that from main;

 

[Herman09851]

You are declaring the Fx and Fy twice. Remove that from main;

Thank you!

 

[Deleted member 2829]

The problem is likely to be that you write Force == -Force. This not an assignment, but a comparison. It's a boolean expression, which does not change Force (as you intended it to), but just returns false (unless Force was zero). Make that Force = -Force and things may work better. Remember to change it 3 times 😉 Personally I would use a switch (kwadrant) statement rather than this convoluted if-else tree. Much easier to follow and maintain.

Also, in addition to what BGB suggested, look at the assignments for Fx and Fy. These two
Fx = 0;
Fy = 0;
are useless, as they will be given values right after the if statement. Probably not really important, but not good coding.