Multidimensional array in C

Question

I'm trying to create a 2D array from the data read from .txt file.
The data in 'data.txt' look like belows:

A;B;4
A;C;5
B;C;8

Assume it is symmetry.
Is there any way to create a 2D matrix [i][j] and print in d[i][j] = value?

Appreciate your comments/suggestion.

Answer 1

2D arrays are useful when the dimensions are known at compile time. If this is the case, other answers can be useful. If not, a 2D array isn't for you.

I suggest using a simple 1D array, allocated (malloc) to have n*n entries.
Then, to access cell i/j, use array[i*n+j].

Another approach is to allocate an array of pointers to arrays. Creating it is more complicated, but you can access it as array[i][j].

Answer 2

int tda[3][3];
tda[1][2] = 'x';

You can also use malloc for a dynamically-sized array.

Answer 3

As you wrote:

#include <stdio.h>

#define N 4

int main(int argc, char **args) {
    int A[N][N], i, j;

    for (i = 0; i < N; i++)
        for (j = 0 ; j < N; j++)
            A[i][j] = i + j;

    for (i = 0; i < N; i++) {
        for (j = 0; j < N; j++)
            printf("%d ", A[i][j]);
        printf("\n");
    }
}