can anyone show me how to input a value into one of my classes and then output it?

[mgm11]

#include <iostream>
#include <cstdlib>

using namespace std;


class Temperature
{

public:
static Temperature Fahrenheit (double f);
static Temperature Celsius (double c);
static Temperature Kelvin (double k);
private:
Temperature (double temp);
double _temp;
};
Temperature::Temperature (double temp):_temp (temp) {}

Temperature Temperature::Fahrenheit (double f)
{
return Temperature ((f + 459.67) / 1.8);
}

Temperature Temperature::Celsius (double c)
{
return Temperature (c + 273.15);
}

Temperature Temperature::Kelvin (double k)
{
return Temperature (k);
}

int main()
{
  
int option;


cout<<"1. Input the temperate (degree and unit)"<<endl;
cout<<"2. Display the temperate as current unit"<<endl;
cout<<"3. Convert and display the temperate as Celsius"<<endl;
cout<<"4.Convert and display the temperate as Fahrenhe"<<endl;
cout<<"5. Convert and display the temperate as Kelvin"<<endl;
cout<<"0. Exit the program"<<endl;

//cin>>option;
//as these were functions they need to be out of main (which is a function, you cannot have two functions inside each other!


//}

return(0);
}

[hanst99]

Your class is pretty useless right now. You do have private members, but not a single non-static method that could access them. Did you really understand this whole class thing?

[chenqi07]

public:
static Temperature* GetInstance(double t) 
{
if (m_pInstance == NULL)
{
m_pInstance = new Temperature(t);
return m_pInstance;
}
else
{
return m_pInstance;
}
}

private:
static Temperature * m_pInstance;

I don't know what exactly you want. But in this way, you could use Temperature *pt = Temprature::GetInstance(t) to get a pointer to a temperatue object.

[b2ee]

The using of the constructor in your class is not usual, do you really want to create a new object in this way? You could do better.

And also I couldnt' see any link between the topic tile and the class definition. Do you really ask:
"can anyone show me how to input a value into one of my classes and then output an object of a same class? If yes, the questions itself is not usual. You can do it technically, but usually C++ doesn't do it in this way in my understanding.

b2ee

[chenqi07]

@b2ee
Declaring constructor as private is usually used to initialize one and only one object, as shown above. This technique is generally used in Singleton Pattern.

[b2ee]

Thanks for the indication. In my code, the Singleton pattern is not implemented by this way. An obvious drawback of the private constructor is: others class will never get chance to inherit the class.