Cannot pass my matrix of structs to a function after using malloc function

Question

I need to create a matrix containing structs. My struct:

typedef struct {
    int a;
    int b;
    int c;
} myStruct;

My method to create matrix

Answer 1

In C89, WIDTH must be a constant and you can simply pass the matrix this way:

#include 

#define WIDTH  5

typedef struct {
    int a;
    int b;
    int c;
} myStruct;

void init_matrix(myStruct matrix[][WIDTH], int height) {
    for (int i = 0; i < height; i++) {
        for (int j = 0; j < WIDTH; j++) {
            matrix[i][j].a = matrix[i][j].b = matrix[i][j].c = 0;
        }
    }
}

int main() {
    int height = 5;
    myStruct (*matrix)[WIDTH] = malloc(height * sizeof *matrix);
    if (matrix) {
        init_matrix(matrix, height);
        ...
        free(matrix);
    }
    return 0;
}

In C99, if variable length arrays (VLAs) are supported, both WIDTH and HEIGHT can be variable but the order of arguments must be changed:

#include 

typedef struct {
    int a;
    int b;
    int c;
} myStruct;

void init_matrix(int width, int height, myStruct matrix[][width]) {
    for (int i = 0; i < height; i++) {
        for (int j = 0; j < width; j++) {
            matrix[i][j].a = matrix[i][j].b = matrix[i][j].c = 0;
        }
    }
}

int main() {
    int height = 5;
    int width = 5;
    myStruct (*matrix)[width] = malloc(height * sizeof *matrix);
    if (matrix) {
        init_matrix(width, height, matrix);
        ...
        free(matrix);
    }
    return 0;
}