Thread: Function to read data from file to array

Hi everyone,
I am writing a function that will read int numbers from a file and store the numbers into an array, but I an having a hard time with it. on of the problems being that I need it to return the number of items stored in the array when it is done, so that i can use it in another function,
Below is the code. Any pointers and help would be greatly appreciated.


#include <stdio.h>
int* readtopps (char fn[]){
int data[];
int n,i;
FILE* fp;

fp=fopen(fn,"r");
fscanf(fp,"%d",&n);
data=(int*)malloc(sizeof(int)*n);
for (i=0;i<n;i++)
fscanf(fp,"%f",&data[i]);
fclose(fp);
return(data);
}
now, I thougth of making it return a structure containing an int(numofelems) and an array(cardnum), but how would i do that?

Like this

Code:

#include <stdio.h> 
#include <stdlib.h> 
int* readtopps (char fn[], int *num ){ 
  int *data; 
  int n,i; 
  FILE* fp; 

  fp=fopen(fn,"r"); 
  fscanf(fp,"%d",&n); 
  data=malloc(sizeof(int)*n); // if you need the cast, stop using C++
  for (i=0;i<n;i++) 
    fscanf(fp,"%f",&data[i]); 
  fclose(fp);
  *num = n;  // store 'n' where the caller can see it
  return(data); 
}

Call it like so
int num;
int *ptr;
ptr = readtopps( "file", &num );

so ptr is a pointer to the array data, right? since that's what readtopps returns.

>so ptr is a pointer to the array data, right? since that's what readtopps returns.
But take a look at num passed as an extra parameter to readtopps(), you have the number of elements there.