[c] How to pass 2D array (matrix) in a function in C?

I need to do this to persist operations on the matrix as well. Does that mean that it needs to be passed by reference?

Will this suffice?

void operate_on_matrix(char matrix[][20]);

Easiest Way in Passing A Variable-Length 2D Array

Most clean technique for both C & C++ is: pass 2D array like a 1D array, then use as 2D inside the function.

#include <stdio.h>

void func(int row, int col, int* matrix){
    int i, j;
    for(i=0; i<row; i++){
        for(j=0; j<col; j++){
            printf("%d ", *(matrix + i*col + j)); // or better: printf("%d ", *matrix++);
        }
        printf("\n");
    }
}

int main(){
    int matrix[2][3] = { {0, 1, 2}, {3, 4, 5} };
    func(2, 3, matrix[0]);

    return 0;
}

_{Internally, no matter how many dimensions an array has, C/C++ always maintains a 1D array. And so, we can pass any multi-dimensional array like this.}

2D array:

int sum(int array[][COLS], int rows)
{

}

3D array:

int sum(int array[][B][C], int A)
{

}

4D array:

int sum(int array[][B][C][D], int A)
{

}

and nD array:

int sum(int ar[][B][C][D][E][F].....[N], int A)
{

}

I don't know what you mean by "data dont get lost". Here's how you pass a normal 2D array to a function:

void myfunc(int arr[M][N]) { // M is optional, but N is required
  ..
}

int main() {
  int somearr[M][N];
  ...
  myfunc(somearr);
  ...
}