Adding to an array in an external file, and adding elements to it.


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# 1  
Adding to an array in an external file, and adding elements to it.

I have an array in an external file, "array.txt", which contains:


Code:
char *testarray[]={"Zero", "One", "Two", "Three", "Four", "Five", "Six", "Seven", "Eight", "Nine"};

I want to be able to add an element to this array, and have that element display, whenever I call it, without having to recompile the source code. Is this possible?

--- Post updated at 09:23 PM ---

I should also mention, that I am using
Code:
#include "array.txt"

with this file.
# 2  
If you keep a file like this, it's much easier to add to:
Code:
Zero
One
Two
Three
Four
Five
Six
Seven
Eight
Nine

Then you translate it into an array with
Code:
( echo "static char *testarray[]={" ; xargs printf "\"%s\"," < arr ; echo "};" ) > array.h

It ending in a comma is allowable in C, which makes this easier.

The 'static' is to prevent linker errors if you use this in more than one file.
# 3  
Ok. Thank you for that. But, I can't quite understand how I implement that into my code...
# 4  
Is it a function, is it a shell script, what exactly is it?
# 5  
Code:
cat text.txt
>the table stands at the window

Code:
cat test.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
	int i;
//	char **testarr = (char**)malloc(sizeof(char*));
	char *dl = ", \t\n";
	char *word;
	FILE *file;
	file = fopen("text.txt", "r");

	fseek(file, 0l, SEEK_END);
	long size = ftell(file);
	char *buf = (char*)malloc(size * sizeof(char));
	fseek(file, 0l, SEEK_SET);
	fread(buf, sizeof(char), size, file);
	fclose(file);

	char **testarr = (char**)malloc(size * sizeof(char*));
	word = strtok(buf, dl);
	for(i=0; word != NULL; i++) {
		testarr[i] = (char*)malloc(strlen(word));
		strcpy(testarr[i], word);
		word = strtok(NULL, dl);
	}
        free(buf);

	for(int j = 0; j < i; j++) {
		printf("%s\n", testarr[j]);
                free(testarr[j]);
        }
        free(testarr);
}

Code:
./test
the
table
stands
at
the
window

--- Post updated at 10:46 ---

fixed the code, commented out the wrong line Smilie

--- Post updated at 11:41 ---

Something I am confused, I can not properly allocate memory for addresses in a dynamic array

--- Post updated at 12:34 ---

I fixed in a dynamic array.
But in the strtok function, the valgrind shows one error
Code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main() {
	int i;
	char *dl = ", \t\n";
	char *word;
	FILE *file;
	file = fopen("text.txt", "r");

	fseek(file, 0l, SEEK_END);
	long size = ftell(file);
	char *buf = (char*)malloc(size * sizeof(char) + 1);
	fseek(file, 0l, SEEK_SET);
	fread(buf, sizeof(char), size, file);
	fclose(file);

	char **testarr = (char**)malloc(sizeof(char*));
	word = strtok(buf, dl);
	for(i=0; word != NULL; i++) {
		testarr = (char**)realloc(testarr, sizeof(char*) + sizeof(char*) * i);
		testarr[i] = (char*)malloc(strlen(word) + 1);
		strcpy(testarr[i], word);
		word = strtok(NULL, dl);
	}
	free(buf);

	for(int j = 0; j < i; j++) {
		printf("%s\n", testarr[j]);
		free(testarr[j]);
	}
	free(testarr);
}

--- Post updated at 13:16 ---

Collected the program with debug information and Valgrind calmed down Smilie

--- Post updated at 13:27 ---

Add words to the file
Code:
cat text.txt
the table stands at the window
and the picture hang on the wall

Run without recompiling
Code:
./test
the
table
stands
at
the
window
and
pucture
hung
on
the
wall


Last edited by nezabudka; 03-14-2019 at 07:49 AM..
This User Gave Thanks to nezabudka For This Post:
# 6  
Awesome. Thank you. Smilie
# 7  
Thanks to everyone for their help. Now, i'd like to know, if possible, how do I display this array?

--- Post updated at 07:49 PM ---

Let me elaborate a little more on what i'd like to see... I'd like to be able to traverse the elements in the array with the arrow keys. That's essentially what i'm trying to do. I already have the code ready to accomplish this. I just need to be able to feed the function the name of the array. And that's it.


Thanks.
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