CODEWITHSUNDEEP
carrayscharmalloc
Darxor
Darxor

Reputation: 1

C - Scanning a dynamic 2D array of chars and allocation

I would like to have a dynamic 2D array of chars, max 200 and scan to it. I am not really sure how to do this, all I came up with is to define the dynamic arrays (and I don't even know if it is right): 

char **arr = (char **)malloc( (len+1) * sizeof(char*) );
  for (i=0;  (len+1)>0; i++)
    char *arr1 = (char *) malloc ( (len+1) * sizeof(char) );

But I am not sure what to put in the (len) - let's say I would like an array of 51x150, depending on the scanned input. How to allocate the array based on the scanned value and print it?

An example of input: 

####.#...##
##.##.#.###
##.###.#.##
#.##.##.#..

Upvotes: 0

Views: 562

Answers (1)

Lundin
Lundin

Reputation: 214300

You probably want to use a real 2D array and not a segmented look-up table.

size_t x = 51;  // user input
size_t y = 150; // user input

char (*arr)[y] = malloc( sizeof(char[x][y]) );
...
arr[i][j] = something;
...
free(arr);

This is much faster and safer than a segmented look-up table. This also allows you to memcpy data in and out of the array, even if that data is larger than one line.

Upvotes: 2

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