File between functions

[skg29]

Passing file between functions.

In the main, there is a switch case. Option 1 executes Function named Main_Linear_Reg()

#include "Pearson.h"
void Main_Linear_Reg();
void Main_Linear_Reg()
{
int  n, i;
     printf("Enter Number Of Pairs:\t");
            scanf("%d", &n);
            struct Pearson Per[n];
            for(i=0; i<n; i++)
            {
                printf("Pair: %d\n",i+1);
                InDetails(&Per[i]);
                printf("\n");
            }
            system("cls");
            for(i=0; i<n; i++)
            {
                printf("Pair: %d\n",i+1);
                DiDetails(Per[i]);
                printf("\n");
            }
FILE *fptr;
            fptr= fopen ("Data/t-test_Linear Regression.txt","w");
            for(i=0; i<n; i++)
            {
                FileDetails(Per[i], &fptr);
            }

The Functions used are from Pearson.h :

struct Pearson
{
    float X;
    float Y;
};


void InDetails(struct Pearson *P);
void DiDetails(struct Pearson P);
void FileDetails(struct Pearson P, FILE *OutFile);
void InDetails(struct Pearson *P)
{
    printf("X:\t");
    scanf("%f", &P->X);
    printf("Y:\t");
    scanf("%f", &P->Y);
}


void DiDetails(struct Pearson P)
{
    printf("X:\t%3.3f, Y:\t%3.3f",P.X,P.Y);
}
void FileDetails(struct Pearson P, FILE *OutFile)
{
    fprintf(OutFile,"X:\t%3.3f, Y:\t%3.3f",P.X,P.Y);
}

I get the following error:
5 main.c In file included from main.c 
 MainLin.h In function `Main_Linear_Reg': 
62  [Warning] passing arg 2 of `FileDetails' from incompatible pointer type

What i want to do in this case is print all X and Y values of the struct to a file. If there is an alternative way, do let me know. Thanks.

[Subsonics]

FILE *fptr;
            fptr= fopen ("Data/t-test_Linear Regression.txt","w");
            for(i=0; i<n; i++)
            {
                FileDetails(Per[i], &fptr);
            }

FILE *fptr, declares fptr as a pointer. FileDetails expects a pointer, you give the address of fptr itself by adding the ampersand, which is why you get a complaint about an incompatible pointer type. Using a plain fptr as an argument is how you declared your interface, so just pass fptr.

[skg29]

I removed the & before fptr. But the file is still empty. The program does not write anything.

[Subsonics]

I removed the & before fptr. But the file is still empty. The program does not write anything.

"still"? you never mentioned this as part of your problem, of course that would have been a consequence of the above but..

Start by adding basic error checking after you open the file. Check that you were able to successfully open it, that is mandatory code that you should never leave out. Test if the file pointer is NULL after you attempt to open it, and use perror() to get a sensible error message out of it.

[skg29]

I close everything, and opened again. rebuilt all and its working thnks