6. (10分)使用linked list運用C語言實作stack： typedef struct node { int value; node *next;} void push (node **top, int new_value) { // assume top is not null node *new_node = (node *) malloc (sizeof (node)); // 實作以下敘述 // add new_node to stack by top } int pop (node **top) { // assume top is not null int value; node *deleting_node = *top; // 實作以下敘述 // remove the deleting node from stack, get the value of deleting node free(deleting_node); return value; }