Read lines of file, put each line into an array, then print

Question

I just figured out how to do this with integers so decided to give it a go with strings and got stuck.

Here is what is in my file "kw":

keyword0
keyword1
keyword2
keyword3

With this current code I'm getting "error: format '%s' expects argument of type 'char *', but argument 3 has type 'char **'

#include <stdio.h>

int main () {
    FILE *pFile;

    pFile = fopen("kw", "r");

    if (pFile != NULL) {

        char *a[3];
        int i;

        for(i = 0; i <= 3; i++) {
            fscanf(pFile, "%s", &a[i]);
            printf("%s\n", a[i]);
        }
    }
    return 0;
}

Could someone point me in the right direction here? Thank you.

Sergey Kalinichenko · Accepted Answer · 2012-10-02 03:05:40Z

2

There are several problems with this code:

You are going through four elements of the array a, while the array has only three elements.
You did not allocate space for the strings that you are reading with scanf.
You do not pass the address of address when you read strings.

To fix the first problem, change <= for != or <, like this:

for(i = 0; i != 3; i++)

To fix the second and the third problem, use malloc:

a[i] = malloc(21*sizeof(char));
fscanf(pFile, "%20s", a[i]);

Once you are done with the data that you allocated, don't forget to free the strings:

for(i = 0; i != 3; i++) {
    free(a[i]);
}

answered Oct 2, 2012 at 3:05

Sergey Kalinichenko

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2 Comments

Benjamin Danger Johnson Over a year ago

actually, the code is fine with "for(i = 0; i <= 3; i++)" that is supposing he fixes the array a to hold 4 elements. But you should probably use "for (i = 0; i < 4; i++)" although it's the performance gain is trivial, it used to be much faster to use "<" over "=". Other than that, the above answer is definitely the way to go.

user1455112 Over a year ago

Just what I needed to know. Thanks a bunch.

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