Thread: Help with returning arrays using pointers

I'm writing a program that needs to have several functions. Other than main, one of them is a function called get_inputs. In get_inputs, the program will get information from the user, and then return all 4 of the values recieved to main.

I know that pointers need to be used here, so here is what I think needs to be done, but I know that it wont work.

First of all, I need to properly call the function in main. I also need to find out if the way that I've implemented the pointers is correct. I'm not sure what I need to put inside the braces in the userInput array. I don't even know if the format is correct. I've done some research, but it is really confusing for me. Could I get some help with both of these?

NOTE: there are more functions in the program, but they dont apply to this.

Code:

#include <stdio.h>
#include <stdlib.h>
#include <math.h>

/* Rows represent the months of the year, Columns represent the hours in a typical day */
#define NROWS 11
#define NCOLS 23
#define TRUE 1
#define FALSE 0
#define INSTALLATION_COST 2000

float panelEfficiency = 0.18, inverterEfficiency = 0.90;

int main()
{
      int houseEnergyREQ, numBatteries, numInverters;
      int flag = TRUE;
      float userInput[4], panelCost, inverterCost, batteryCost,
            panelArea, batteryRating = 4.8, inverterRating = 5.0,
            insolDayMin, maxHourPanelOutput, insolHourMax, totalCost;
      
      float *ptr_to_userInput;
      
      float insolation_Matrix[NROWS][NCOLS];

      
      while(flag)
      {
            float get_inputs(float userInput[]);
            
            /* Switch userInput array to meaningful terms */
            userInput[0] = houseEnergyREQ;
            userInput[1] = panelCost;
            userInput[2] = inverterCost;
            userInput[3] = batteryCost;
            
            /* Equation to calculate panelArea */
            panelArea = houseEnergyREQ/(insolDayMin*panelEfficiency*inverterEfficiency);
            
            /* Equation to calculate maxHourPanelOutput */
            maxHourPanelOutput = insolHourMax*panelArea*panelEfficiency;
            
            /* Equation to calculate numbatteries */
            numBatteries = ceil(houseEnergyREQ/(inverterEfficiency*batteryRating));
            
            /* Equation to calculate numInverters */
            numInverters = ceil(maxHourPanelOutput/(inverterEfficiency*inverterRating));
            
            /* Equation to calculate total cost */
            totalCost = panelArea*panelCost + numBatteries*batteryCost + numInverters*inverterCost
                         + INSTALLATION_COST;
            
            printf("The total cost of your Solar panel system is %.2f $. \n", totalCost);
            
            /* Give user an option to quit program */
            printf("Do you wish to continue? (y/n) \n");            
            if(getchar() == 'n')
            {
                  flag = FALSE;
            }
      }

      system("PAUSE");
}
/*---------------------------------------*/
/* Function to get inputs houseEnergyREQ, panelCost, inverterCost, batteryCost */
float get_inputs(float userInput[4], *ptr_to_userInput)
{
      *ptr_to_userInput = &userInput[]
      
      printf("This program will calculate the total cost of your solar panel system.");
      printf("Enter the daily required amount of energy for your house, in kWh : \n");
      scanf("%f", &userInput[0]);

      printf("Enter the cost of solar panels (per m^2), power inverters and batteries: \n");
      scanf("*f %f %f", &userInput[1], &userInput[2], &userInput[3]);

      return *ptr_to_userInput;
}

How would I do that?

Oh, so if I change the function from float to void, I don't need a return statement?