初始化递归函数内部的结构？ （在C中）

Question

我有一个关于使用矩阵行列式的递归定义的问题，我们在其中传递一个矩阵结构，其中包含矩阵及其行数/列数，但每次我尝试调用它时都会出现分段错误：

int det(struct Matrix *A){

/* A recursive definition of the determinant.*/

//If it's a single element, return the element
if( A->row == 1 && A->col == 1) {
    return A->mat[0][0];
}

if(A->squareQ == 0){
    puts("Matrix isn't square.");

    return -999999999;
}

int DET = 0;
int n = A->row;

//Initialize memory for the (n-1)x(n-1) cofactor matrices

int i,j;
struct Matrix *COF = malloc(sizeof(struct Matrix));

COF->row = n-1;
COF->col = n-1;
COF->squareQ = 1;

//Now, begin building cofactors

int I,J; 

int k = 0, l = 0;   
int temp;
for(I = 0; I < n; I++){
    for(J = 0; J < n; J++){

        for(i = 0; i < n; i++){
            if( i == I ) continue;
            for(j = 0; j < n; j++){
                if( j == J ) continue;              
                temp = A->mat[i][j];
                COF->mat[k][l] = temp;
                l++;
            }
            l = 0;
            k++;              
        }
        k = 0;
        DET += pow(-1,I+J)*det(COF);
    } 
}

free(COF);

return DET;

}

并且它位于COF-> mat [k] [l] =临界发生的临界值。如何将元素分配给COF并将其传递给递归调用？感谢