Reading from file into a dynamically allocated array of strings

Question

Here is my code so far. My array just isn't being populated. The problem is happening with fscanf. I know it reads in the characters just fine because I've tried reading them into a generic char pointer / string and it reads just fine. Just not sure how to copy the chars into the complicated array. Pointer to a pointer :O Text file format might something like..

Alice
Bob
Jerry
Ted

My code:

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

int main()
{
    int lineCount = 1;
    char* fileInput;
    char c[100];

    int allocatedBytes = 0;

    fileInput = (char*)malloc(100*sizeof(char));
    printf("File name: ");
    gets(fileInput);

    FILE * fptr;

    if ((fptr = fopen(fileInput, "r")) == NULL)
    {
        printf("Error! opening file");
        // Program exits if file pointer returns NULL.
        exit(1);
    }

    //get number of names before dynamic array allocation
    for(char c = getc(fptr); c!= EOF; c=getc(fptr))
        if(c == '\n')
            lineCount = lineCount + 1;

    char **names = malloc(lineCount * sizeof(char *));

    for(int i=0; i<lineCount; i++)
        names[i] = (char *)malloc(100);

    int i=0;
    while((fscanf(fptr, "%99s", names[i]))!=EOF)
        i++;

    for(int i=0; i<lineCount; i++)
        printf("%s\n", names[i]);
}

You read through the file when you count lines. You need to rewind the file pointer to then read the data. — 001, Sep 22 '19 at 17:33
[The `gets()` function is too dangerous to be used — ever!](https://stackoverflow.com/questions/1694036/why-is-the-gets-function-dangerous-why-should-it-not-be-used) Also, it is a good idea to report error message on standard error (`stderr`) rather than standard output (`stdout`). And, when reporting that you failed to open a file, it is a good idea to include the file name — it helps people check whether they made a typo, for example. Including error information (via `errno` and `` and `strerror()` from ``) is often a good idea. — Jonathan Leffler, Sep 22 '19 at 18:25

score 0 · Answer 1 · answered Sep 22 '19 at 17:47

The file pointer(fptr) used in fgetc is reused for fscanf also. fget might have changed File pointer (fptr ) structure value like reading position and writing position. Try using another file pointer for fscanf. In this code getc is used instead of fgetc.So, ensure this also.

Reading from file into a dynamically allocated array of strings

1 Answers1