为什么在这个平衡括号检查 C 程序中堆栈没有被清空？

Question

I am trying to check whether the given array of parenthesis are balanced or not using linked list implemented stack.I have declared a global struct pointer. And the rest of the code is this.

struct node *Head;
struct node
    {
        char data;
        struct node *next;
    };
    
    struct node *getnewnode(char x)
    {
        struct node *temp = (struct node *)malloc(sizeof(struct node));
        temp->data = x;
        temp->next = NULL;
        return temp;
    }
    
    void push(char x)
    {
        printf("Pushing:%c\n", x);
        struct node *temp = getnewnode(x);
        if (Head == NULL)
            Head = temp;
        struct node *temp2 = Head;
        temp->next = temp2;
        Head = temp;
    }
    
    void pop()
    {
        struct node *temp = Head;
        if (temp == NULL)
            printf("Nothing to POP");
        else
        {
            printf("POPing : %c\n", Head->data);
            Head = temp->next;
            free(temp);
        }
    }
    
    int main()
    {
        Head = NULL;
        char C[] = "{()}";
    
        for (int i = 0; i < strlen(C); i++)
        {
            if (C[i] == '{' || C[i] == '[' || C[i] == '(')
            {
                push(C[i]);
                printf("Push :%c\n", Head->data);
            }
            else if (C[i] == '}' || C[i] == ']' || C[i] == ')')
            {
                if (Head == NULL)
                {
                    printf("nothing in stack\n");
                }
                else if (C[i] == ']' && Head->data == '[')
                    pop();
    
                else if (C[i] == '}' && Head->data == '{')
                    pop();
    
                else if (C[i] == ')' && Head->data == '(')
                    pop();
    
                //else
                //  return 0;
            }
        }
    
        printf("Present Stack:%c\n", Head->data);
        if (Head->data == -1)
            printf("Balanced");
        else if (Head->data != -1)
        {
            printf("not Balanced");
        }
    }

The output that I am getting is this

 Pushing:{ 

 Push :{
  
 Pushing:(

 Push :(
  
 POPing : (

 POPing : {

 Present Stack:ÿ 

 not Balanced

As you can see that the all the elements of the array are getting popped, still the output is not balanced. There is still the value 'ÿ' in the stack which I have no idea of. Could someone kindly point out what's wrong in this code. Am I missing something.

Answer 1

Your push should just be

void push(char x)
{
    printf("Pushing:%c\n", x);
    struct node* temp = getnewnode(x);
    temp.next = Head;
    Head = temp;
}