Allocating dynamic memory class in void function

[RomiEdu]

I am having trouble allocating dynamic memory to a class in a void function and later using it in the main function.
When I try to run it, I get the following message in lines 52 to 5:
"error: request for member 'set_value' in '*(Well + ((sizetype)(((unsigned int)n) * 4u)))', which is of pointed type 'WellSlice*' (maybe you meant to use '->' ?)"
I also get "error: invalid conversion from 'int' to 'int*' [-fpermissive]" on line 64 and "error: intializing argument 1 of 'void ReadInputData(int*, WellSlice**)' [-fpermissive]" on line 35.

PS: The Input.txt file contains the number of data points followed by 4 variables for each data point, such as:
5
10 25 30 0.5
11 30 40 1
9 25 5 10
6 87 3 2

#include <iostream>
#include <new>
#include <fstream> 
#include <cstdio>
#include <string>
#include <istream>
#include <ios>
#include <iomanip>

using namespace std;


class WellSlice{
    double x,y, 
           pressure,
           flowrate;

public:
    void set_value (double, string);
    void print_values ();
};


void WellSlice::set_value (double value, string variable){
if (variable =="x1") {x = value;}
else if (variable =="y1"){y = value;}
else if (variable =="pressure1"){pressure = value;}
else if (variable =="flowrate1"){flowrate = value;}
}

void WellSlice::print_values (){ 
cout << x << ", " << y << ", " << pressure << ", " << flowrate;
}

void ReadInputData (int *i, WellSlice **Well){
    int n;
    ifstream InputData ("Input.txt");
    double x1, y1, pressure1, flowrate1;
    x1 = y1 = pressure1 = flowrate1 = 0;

    if (InputData.is_open()){
        int* iaux; iaux = (int*)i;
        InputData >> *iaux;
        *Well = new (nothrow) WellSlice[*i]; 

        for (n=0; n<*i; n++){    
            InputData >> x1;
            InputData >> y1;
            InputData >> pressure1;
            InputData >> flowrate1;
            if (InputData.eof() == true) break;  
            *Well[n].set_value(x1, "x1");
            *Well[n].set_value(y1, "y1");
            *Well[n].set_value(pressure1, "pressure1");
            *Well[n].set_value(flowrate1, "flowrate1");
        }
    }
}

int main(){
    WellSlice * Well;
    int i, n;

    ReadInputData (i, &Well);

    cout << "\nYou have entered: ";
    for (n=0; n<i; n++){
        cout << "\nWell slice number " << (n+1) << ":\n";
        Well[n].print_values();
    }
    delete[] Well;  

    return 0;

}

[MiiNiPaa]

You essentually have: *( Well[n].set_value(x1, "x1") );
You want: (*Well[n]).set_value(x1, "x1");
better way: Well[n]->set_value(x1, "x1");

[RomiEdu]

Thank you very much for your answer, that was precisely the problem I was having.

However, another problem has come up: For some reason, the program is crashing when I try to run it. I used many cout commands to find out that it is crashing when, for n = 1(the second run in the loop), it tries to read line 52.
Any ideas on where it might be going wrong?

Thank you very much!

[ne555]

Making your code obfuscated and then complaining that it doesn't work.

> *Well = new (nothrow) WellSlice[*i];
*Well (or if you prefer Well[0]) is pointing to the memory allocated

So you've allocated an array, the first element would be W[0][0] or (*W)[0]
the second element is W[0][1] or (*W)[1], that is not the same as (*W[1]) which is not dereferenceable.


Use std::vector