Thread: Help with reading strings and opening files PLEASE

I am having a whole lot of trouble so far with this program. The program prompts the user for the name of a file, which contains floating point numbers, to be opened for reading and store the values into an array. The rest of the program is done...I think. My problem is that everytime I try to run the program it prints my error message for not being able to open the file and exits. Where did I mess up with the reading of the filename or opening the file or I dont know

I know the return values for fopen are EOF, NULL and I think 0 or nothing if it works but it still keeps tripping up on the NULL case I guess

This is one of my first programs and ANY help is much appreciated

THANKS

Ive tried many things so far and this is what I have at the moment.....

Code:

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

#define FLUSH while (fgetc(fileDataIn) != '\n')
#define MAX_SIZE_NAME 100
#define MAX_SIZE_FILE 100


int main(void)
{
float data[MAX_SIZE_FILE];
char fileName[MAX_SIZE_NAME];
int fileLength;
float h;
int i;
FILE *fileDataIn;
int result;

printf("Enter File Name: ");
scanf("%s", &fileName);

//open file
fileDataIn = fopen(fileName, "r");

if (fileDataIn == NULL)
	{
	printf("Error: Could not open file %s for read.", fileName);
	exit(1);        
	} //if


	else
         while (fscanf(fileDataIn, "%f", &h) != EOF)
		{
		  for (i = 0; result = fscanf(fileDataIn, "%f", &h); i++)
           	  	if (result != 1)
			{
			  FLUSH;
			} //if
		
	 	data[i] = h; //should store each value read in into consecutive locations in data
         	fileLength = i + 1;

         	} // while
			
 fclose(fileDataIn);


return 0;
}

Thanks for the quick reply master5001

I added your ideas with fgets and strtok but still get the same error.

Could I be saving the .txt file incorrectly?

For that confusing code part..
I was trying to increment i, which would control where in data[] the value would be stored. In my head the code should read in a number and store it in h. Then data[i] = h should store those values in different spots as i is incremented. I think if fscanf returns 0 then im trying to flush out the \n from the file to get to the rest of the data.

The data in the file looks like this

89
23.5
90
1
0
-5.25
10000
25123.90
54321.23
6
55
76
33
104
145
204
32
445
523
-2
-64.6
3
76
33

To be honest, I would write a function that counts lines, and create your data buffer dynamically.

Example:

Code:

size_t count_lines(FILE *file)
{
  size_t n;
  char buffer[4096]; /* 4k should be big enough */

  for(n = 0; fgets(buffer, sizeof(buffer), file); ++n)
    ; /* nothing to do here */

  rewind(file);
  return n;
}

Hey thanks again
Im gonna work on this more later. Hopefully it all goes well!

Thanks I got it all working now. Turns out the main problem was how I was saving the file.

But now I have run into another problem. When I read all of the values into my array I am somehow reading an extra zero. I think it is at the beginning when I store the numbers but im not sure. It adds a zero to my array whenever the file does not even contain a zero.

Any help would again be great!

Code:

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

#define FLUSH while (fgetc(fp) != '\n')
#define MAX_SIZE_NAME 100
#define MAX_SIZE_FILE 100



int main(void)
{
// local declarations in main

float data[MAX_SIZE_FILE];
char fileName[MAX_SIZE_NAME];
int fileLength = 0;
float h;
FILE* fp;
int result;
        //for sorting
int current;
int walker;
float temp;
        //for printing table
int numPrinted = 0;
int j;
        //for average
int k;
float sum = 0;
float average;
        
        
// first print my name
printf("\nNAME: Nathan Vazquez\n\n");
        

printf("Enter File Name: ");
fgets(fileName, sizeof(fileName), stdin);
strtok(fileName, "\n");

//open file
fp = fopen(fileName, "r");
if (fp == NULL)
  {
  printf("Error: Could not open file %s for read.", fileName);
  return EXIT_FAILURE;
  } //if
 while ((result = fscanf(fp, "%f", &h)) != EOF && (fileLength < 100))
        {
          if (result != 1)
           {
             FLUSH;  
           } //if


        data[fileLength++] = h;
        
        } // while

//done opening and storing file



//sort data in file
for(current = 0; current < fileLength; current++)
        {
        //inner loop: Bubble up one element each pass
   
        for (walker = fileLength; walker > current; walker--) 
  
                if (data[walker] < data[walker - 1])
                  {
                        temp                    = data[walker];
                        data[walker]            = data[walker - 1];
                        data[walker - 1]        = temp;
                  } //closes if
        } //closes outer for loop
             
//print out data 
printf("\n\n");
for (j = 0; j < fileLength; j++)
        {
          numPrinted++;
          printf("  %8.2f ", data[j]);

        if (numPrinted >= 5)
                {
                  printf("\n");
                  numPrinted = 0;
                } //closes if

         } // closes for
         
printf("\n\n"); // provides the one line gap between data table and results
   
//prints out the number of elements in the file
printf("There were %d numbers found in file %s\n", fileLength, fileName);
                
// Smallest number found
printf("The smallest number found was: \t%8.2f\n", data[0]);  
//Largest number found
printf("The largest number found was: \t%8.2f\n", data[fileLength]);
             
for(k = 0; k < fileLength; k++)
        {
          sum = sum + data[k];  
        } //for
          
        average = sum / fileLength;   

printf("The average of the values is: \t%8.2f\n", average);
                 
                  
fclose(fp);
return EXIT_SUCCESS;

}

Originally Posted by vart

what will happen with your macro call when the end of file is reached?
what will happen with your macro in the code like

Code:

do
   FLUSH;
while(condition);

?

what will happen with your macro if the variable fileDataIn will be renamed in the code?

Hmmm such things can also result in random crap happening... like I don't know... oh lets say an extra zero....