链表堆栈上的弹出功能
问题描述：
你好，我从弹出函数返回变量时遇到问题. 如果您能帮助我，我会很高兴. 该函数接收到指向列表顶部的指针，并应返回答案，但是指向列表并整数答案时出现问题.
Hello I have a problem to returned variable from my pop function. I will be happy if you could help me. The function receives a pointer to the top of the list and should return the answer but I have a problem with a pointer to the list and intger the answer.
功能代码-
int pop(Node* top)
{
Node* tmp = top;
int ans = tmp->next;
top = top->next;
delete tmp;
return ans;
}
节点-
struct Node
{
int num;
Node* next;
}
Node* top = new Node;
答
As mentioned in my comment you should split this up to two separate functions. One to get the value, and another one to pop (remove) the Node
void pop(Node*& top) { // Note the reference. You want to change the current top node.
// ^
if ( top ) {
Node *tmp = top;
top = top->next;
delete tmp;
}
}
int& top(Node* top) {
if ( top ) {
return top->num;
}
// Throw an appropriate exception if the stack is empty
throw std::out_of_range("Stack is empty.");
}