Question

Hi to all stackoverflow users.
I am trying to build a simple (as an exercise) code that will read from a file and will store the words from a file in an dynamically allocated array. I think I am mallocing wrong. Does anyone see what I am doing wrong?

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

#define ARRSIZE 10

int main(){
    char * myArray = malloc(ARRSIZE*sizeof(char*));
    FILE * p1File;
    char mystring1 [100];
    char word [100];
    int j = 0;
    p1File = fopen ("my1file.txt","r");
    if (p1File == NULL) perror ("Error opening file");
    else{
        while(fgets(mystring1, 100, p1File)){
            int nuRead = sscanf(mystring1, "%s", word);\
            printf("lepo ani magia\n\n");
            if (nuRead > 0){
                strncpy (*myArray[j], mystring1, 100);
                //*myArray[j] = mystring1;
            }
            j += 1;
        } 
    }
}

///////////////////////////////////

my text file is

this
will
probably
work
but
I
am

Answer 1

You’re not allocating space for your strings, just the array of strings. myArray[j] is just an uninitialized pointer. Instead, allocate space for each string in myArray like so:

char *myArray[ARRSIZE]; // No reason for this to be dynamic.
// ...
if (nuRead > 0)
{
    myArray[j] = malloc((strnlen(mystring, 100) + 1) * sizeof(char));
    strncpy (myArray[j], mystring1, nuRead + 1);
}

As user411313 pointed out, sscanf doesn’t return the number of characters matched, but the number of input items matched. Use strnlen (or strlen if you don’t have strnlen) to get the size of the string (and don’t forget to add 1 for the null terminator).