Import a CSV of strings into a multi-dimensional array in C

Question

I am trying to input a text file, in a similar format to a CSV, into a multi-dimensional array, where every element of the array is an array of words for each line. Any help would be much appreciated!

For example, the file input.txt could contain:

Carrot, Potato, Beetroot, Courgette, Broccoli
Dad's oranges, Apple, Banana, Cherry
Pasta, Pizza, Bread, Butter

The structure of the outputted array I am hoping to get from that would be in the form:

[[Carrot, Potato, Beetroot, Courgette, Broccoli], [Dad's oranges, Apple, Banana, Cherry], [Pasta, Pizza, Bread, Butter]]

So you the line:

printf("%s", inputArray[1][0]);

Would print:

Dad's oranges

Answer 1

I am not sure what the question here is. However, looking at your problem statement, and code I see few issues (note that I did not run the code, it is meant to give you an idea):

1. Your varCount will start from 1, as you increment before you put the first word.

2. You are storing an inherently 2-dimensional data into a single dimensional array. That is normally fine, but you need to encode where a line starts, and where it ends. That is missing. If all works, you will get an array of words, with no knowledge of where lines start/end. One way to deal with it is to create a 2D array. Another, is to insert a pointer to known word between the lines. Below is a code snippet that shows inserting a separator

   char *knownWord = "anyword";
   ...
   while (fgets(line, maxLineLength, inputFile))
   {
       token = strtok(&line[0], ",");
       while (token) {
           inputArray[varCount] = token;
           varCount++;
           token = strtok(NULL, ",");
       }
       inputArray[varCount] = knownWord;
       varCount ++;
   }
   

For this the print will happen with something like

    bool atKnownWord = 0;
    printf("[");
    for (i = 0; i < maxWords; i++) {
            if (inputArray[i] == NULL) {
                    break;
            }
            if (inputArray[i] == knownWord) {
                    atKnownWord = 1;
                    printf("]");
                    continue;
            }
            if (atKnownWord) {
                    atKnownWord = 0;
                    printf(", [");
            }
            printf("%s", inputArray[i]);
    }
    printf("]");

Answer 2

You have not allocated the memory to store the token.
Also you should increment varCount after storing the token in an array.

The code can be written as:

#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#define maxLineLength 1000  //Maximum length of a line
#define wordsPerLine 200    //Maximum words in a line
#define maxLines 200        //Maximum lines in an input

int main(int argc, char *argv[])
{
    char line[maxLineLength] = {0};
    char *inputArray[maxLines][wordsPerLine] = {};
    char *ptr, *token;
    int i, j, lines, maxWords = 0;

    FILE *inputFile = fopen("input.txt", "r");

    if (inputFile)
    {
        i = j = 0;
        while (fgets(line, maxLineLength, inputFile))
        {
            token = strtok(&line[0], ",\n");
            while(token)
            {
                if(ptr = malloc(sizeof(char) * (strlen(token)+1))) //whether malloc succeeded
                {
                    if(token[0] == ' ')
                        strcpy(ptr, token+1);
                    else
                        strcpy(ptr, token);

                    inputArray[i][j++] = ptr;
                    token = strtok(NULL, ",\n");
                }
                else
                {
                    printf("malloc failed!\n");
                    exit(1);
                }
            }
            if(maxWords < j)
                maxWords = j;
            i++;
            j = 0;          
        } 
        lines = i;
        fclose(inputFile);

        for(i = 0; i < lines; i++)
        {
            for(j = 0; (j < maxWords) && inputArray[i][j]; j++)
                printf("%s | ", inputArray[i][j]);
            printf("\n");
        }
    }
    return 0;
}