Today I was trying to implement a Stack using Linked List in C, everything was fine until I created a pop function which uses free, once I call the free function my program crashes and then Visual Studio throws Heap Corruption Error message in a new window. All the other functions are working fine except this one, I just can't figure out what's happening. Thanks for all your answers.
Here's my code:
#include <stdio.h>
#include <stdlib.h>
struct Node {
char data;
struct Node *next;
};
void push(struct Node **top, char data) {
struct Node *temp = (struct Node *)malloc(sizeof(struct Node *));
if (temp == NULL) {
printf("Stack overflow.\n");
} else {
temp->data = data;
temp->next = *top;
(*top) = temp;
}
}
void pop(struct Node **top) {
struct Node *aux;
if (*top != NULL) {
printf("Popped element: %c\n", (*top)->data);
aux = *top;
*top = (*top)->next;
free(aux);
} else {
printf("Stack is empty");
}
}
void display(struct Node *top) {
struct Node *aux = top;
while (aux != NULL) {
printf("%c ", aux->data);
aux = aux->next;
}
printf("\n");
}
int main() {
struct Node *root = NULL;
push(&root, 'a');
push(&root, 'b');
push(&root, 'c');
printf("Stack:\n");
display(root);
pop(&root);
printf("\nStack:\n");
display(root);
return 0;
}
You allocated only buffer for a pointer in this line
struct Node *temp = (struct Node *)malloc(sizeof(struct Node *));
In typical environment, size of the structure will be larger than the pointer, so allocated memory won't have enough size.
The line should be
struct Node *temp = malloc(sizeof(struct Node));
or
struct Node *temp = malloc(sizeof(*temp));