C: read (text) file into array, can't see what's wrong? - c

Question

first time posting here. I have looked at a few other peoples ways to do this, and one of the ways was nearly exactly the same way that I am trying to do. But, it doesn't work for me?
#include<stdio.h>
int main()
{
FILE *file;
char buffer[15];
char *text[12];
file = fopen("Text.txt", "r");
if(!file) {
printf("Failed");
return 1;
}
int count = 0;
while(fgets(buffer,sizeof buffer, file) != NULL) {
printf("%s", buffer);
text[count] = buffer;
count++;
}
printf("\n");
for (count=0;count<10;count++) {
printf("%s\n", text[count]);
}
fclose(file);
return 0;
}
Now on another site (while looking for a solution or help I found this http://www.daniweb.com/software-development/c/threads/316766/storing-string-in-a-array-reading-from-text-file
Where the person has done it the same way as me (apart from obviously slight differences in what they're reading etc).
My text file reads:
The
Quick
Brown
Fox
Jumps
Over
The
Lazy
Dog (all on their own lines).
Basically I want to read the file in line by line and save each line in the next space in the array.
In the code when I use the line
printf("%s", buffer);
It prints out each word of each line okay to the console window.
However, when I print out the contents of the array with the for loop it simply prints out "dog, dog, dog..." for each space in the array.
Can someone help me here? Am I doing it wrong?

Answer 1

You haven't allocated any memory for text. And you have to copy the value of buffer as it changes in each iteration. Something like:
while(fgets(buffer,sizeof buffer, file) != NULL) {
printf("%s", buffer);
text[count] = malloc(strlen(buffer) + 1);
strcpy(text[count], buffer);
count++;
}
Also, check the return value of malloc for allocation failure.

Answer 2

The buffer is always the same address, so all the elements of array text contains the same pointer (or are uninitialized).
You should consider (assuming a POSIX system):
initializing all your arrays by zeroing them (and also initialize all pointers to NULL), e.g. memset(buffer, 0, sizeof(buffer)); (and for your line buffer, clear it also at the end of the loop).
duplicating the read string with strdup i.e. code
text[count] = strdup(buffer);
and don't forget to free that when appropriate. Actually, you should check that strdup did not fail by returning a NULL pointer.
use getline to read a line (don't forget to initialize the pointer, perhaps to NULL and to eventually free it).
end your printf formatting string with a newline \n or else call fflush, notably before any input.
use the error code errno to display a better error message. Or just call perror like
file = fopen("Text.txt", "r");
if (!file) {
perror("fopen Text.txt failed");
exit (EXIT_FAILURE);
}
Take the habit to compile with all warnings and debugging information (e.g. gcc -Wall -g on Linux) and learn how to use the debugger (e.g. gdb), notably try running line by line your program.
You might be interested in coding for a strict (non POSIX) but plain C2011 standard. But then you have much less freedom to use many POSIX functions (like strdup etc...). I leave the boring exercise to code for strict C99 compliance to the reader (remember that C99 does not even know about directories and suppose nearly "flat" filesystems), because I am a Posix and Linux fan and don't care about non Posix systems (in particular I don't care and did not use Windows or Microsoft systems since 1990).
Also, try to read the code of some free software project (e.g. from freecode). You'll learn a lot

Answer 3

There are two problems in the code:
In the while loop you're storing the same pointer (buffer) over and over again into the array of pointers and you are overwriting the buffer contents too. You should probably advance the buffer pointer by the length of each read string.
In the for loop you're destroying the actual line count and potentially dereferencing uninitialized pointers. Don't do that.