Reading data from a file into a structure array (C) - c

Question

I'm trying to build a simple function that will take in a data file, and assign various values from the data file into a global array of structures. However, I'm having trouble getting it to work quite right. I've written what I believe is most of the needed code, but my test line printf("time is %d\n", BP[i].time); simply reads out "Time is 0." 10 times, leading me to believe the values aren't getting assigned to the structure array like I imagined they would be.
How can I proceed further?
Example Data File (.txt):
0001 553 200
0002 552 100
.... ... ...
Current Code:
#include <stdio.h>
#include <stdlib.h>
// Function Prototype
void readFileBP(char fileName[1000]);
// Definition of BP Structure
struct bloodPressure
{
int *time;
int *sys;
int *dia;
}BP[50]; // end struct BP
int main()
{
char fileName[1000] = "C:\\Users\\User\\Desktop\\DataFiles\\BP_1.txt";
readFileBP(fileName);
int i = 0;
for (i; i<10; i++)
{
printf("Time is %d\n", BP[i].time);
}
} // end int main()
void readFileBP(char fileName[1000])
{
FILE *filePtr; // declare file pointer
int time;
int sys;
int dia;
int position = 0;
if (filePtr = fopen(fileName, "r") == NULL) // error check opening file
{
printf("Opening file failed. Please reenter filename.");
exit(1);
} // end if
while (fscanf(filePtr, "%d, %d, %d", &time, &sys, &dia) != EOF) // read in BP values
{
BP[position].time = time;
BP[position].sys = sys;
BP[position].dia = dia;
position++;
} // end while
fclose(filePtr);
} // end void readFile()

Answer 1

Compile with warnings enabled. You should get something like that:
gsamaras#gsamaras-A15:~$ gcc -Wall -o px px.c
px.c: In function ‘main’:
px.c:22:5: warning: statement with no effect [-Wunused-value]
for (i; i<10; i++)
^
px.c:24:9: warning: format ‘%d’ expects argument of type ‘int’, but argument 2 has type ‘int *’ [-Wformat=]
printf("Time is %d\n", BP[i].time);
^
px.c: In function ‘readFileBP’:
px.c:37:17: warning: assignment makes pointer from integer without a cast [enabled by default]
if (filePtr = fopen(fileName, "r") == NULL) // error check opening file
^
px.c:37:5: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
if (filePtr = fopen(fileName, "r") == NULL) // error check opening file
^
px.c:45:27: warning: assignment makes pointer from integer without a cast [enabled by default]
BP[position].time = time;
^
px.c:46:26: warning: assignment makes pointer from integer without a cast [enabled by default]
BP[position].sys = sys;
^
px.c:47:26: warning: assignment makes pointer from integer without a cast [enabled by default]
BP[position].dia = dia;
^
px.c: In function ‘main’:
px.c:26:1: warning: control reaches end of non-void function [-Wreturn-type]
} // end int main()
^
Isn't that enough to get you started? It was for me! :)

Answer 2

I made some changes and ran it just now.
#include <stdio.h>
#include <stdlib.h>
// Function Prototype
void readFileBP(char fileName[1000]);
// Definition of BP Structure
struct bloodPressure
{
int time;
int sys;
int dia;
}; // end struct BP
struct bloodPressure BP[50];
int main()
{
char *fileName = "file.txt";
readFileBP(fileName);
int i = 0;
for (i; i<10; i++)
{
printf("Time is %d\n", BP[i].time);
}
getch();
}
void readFileBP(char fileName[1000])
{
FILE *filePtr; // declare file pointer
int time=0;
int sys=0;
int dia=0;
int position = 0;
filePtr= fopen(fileName,"r");
while (fscanf(filePtr, "%d, %d, %d", &time, &sys, &dia) != EOF) // read in BP values
{
BP[position].time = time;
BP[position].sys = sys;
BP[position].dia = dia;
position++;
} // end while
fclose(filePtr);
} // end void readFile()
The output is now:
Time is 1
Time is 553
Time is 200
Time is 2
Time is 552
Time is 100
Time is 0
Time is 0
Time is 0
Time is 0

Answer 3

try changing the line :
while (fscanf(filePtr, "%d, %d, %d", &time, &sys, &dia) != EOF)
to
while (fscanf(filePtr, "%d%d%d", &time, &sys, &dia) != EOF)
also here's what i tried out and it seems to work based on the tests i've done
#include <stdio.h>
#include <stdlib.h>
#define MAX_ARRAY_SIZE 50
typedef struct BloodPressure
{
int time;
int sys;
int dia;
}BloodPressure;
BloodPressure bloodPressure[MAX_ARRAY_SIZE];
void ReadFile(char *fileName);
int main(int argc, char *argv[])
{
char *fileName = "BP_1.txt";
ReadFile(fileName);
int i = 0;
for (i = 0; i < MAX_ARRAY_SIZE; i++)
{
printf("Dia is : %d\n", bloodPressure[i].dia);
printf("Sys is : %d\n", bloodPressure[i].sys);
printf("Time is : %d\n", bloodPressure[i].time);
printf("\n");
}
exit(EXIT_SUCCESS);
}
void ReadFile(char *fileName)
{
FILE *filePtr = NULL;
int i = 0;
if ((filePtr = fopen(fileName, "r")) == NULL)
{
printf("Error : Unable to open %s for reading\n");
exit(EXIT_FAILURE);
}
while (fscanf(filePtr, "%d%d%d", &bloodPressure[i].dia, &bloodPressure[i].sys, &bloodPressure[i].time) != EOF)
{
i++;
}
fclose(filePtr);
}