Link List, Jamming Console - c

Question

When i compile this link list my Console Jams after entering the first two intergers. The purpose of the programme is to save the input from scanf into Memory and then output them onto the screen, after this i intend to have the programme save the inputs into a text file.
#include <stdio.h>
#include <stdlib.h>
/*********************************************************
* Node to represent a packet which includes a link reference*
* a link list of nodes with a pointer to a packet Struct *
**********************************************************/
struct Packet {
unsigned int Source;
unsigned int Destination;
unsigned int Type;
unsigned int Port;
char *Data;
struct Packet *next;
};
typedef struct Packet node; // Removes the need to constantly refer to struct
/*********************************************************
* Stubs to fully declared functions below *
**********************************************************/
void Outpacket(node **head);
void push(node **head, node **aPacket);
node* pop(node **head);
int main() {
/*********************************************************
* pointers for the link list and the temporary packeyt to *
* insert into the list *
**********************************************************/
node *pPacket, *pHead = NULL;
/*********************************************************
* Create a packet and also check the HEAP had room for it *
**********************************************************/
pPacket = (node *)malloc(sizeof(node));
if (pPacket == NULL)
{
printf("Error: Out of Memory\n");
exit(1);
}
printf("Enter Source Number:\n");
scanf("%i", pPacket->Source);
printf("Enter Destination Number:\n");
scanf("%i", pPacket->Destination);
printf("Enter Type Number:\n");
scanf("%i", pPacket->Type);
printf("Enter Port Number:\n");
scanf("%i", pPacket->Port);
printf("Enter Data Number:\n");
scanf("%c", pPacket->Data);
pPacket->next = NULL;
/*********************************************************
* Push the Packet onto the selected Link List, the function *
* is written so the program will support multiple link *
* list if additional 'pHead' pointers are created. *
* *
**********************************************************
* NOTE: The push parameters are using references to the *
* pointers to get round the pass by value problem caused *
* by the way C handles parameters that need to be *
* modified *
**********************************************************/
push(&pHead, &pPacket);
pPacket = (node *)malloc(sizeof(node));
if (pPacket == NULL)
{
printf("Error: Out of Memory\n");
exit(1);
}
printf("Enter Source Number:\n");
scanf("%i", pPacket->Source);
printf("Enter Destination Number:\n");
scanf("%i", pPacket->Destination);
printf("Enter Type Number:\n");
scanf("%i", pPacket->Type);
printf("Enter Port Number:\n");
scanf("%i", pPacket->Port);
printf("Enter Data Number:\n");
scanf("%c", pPacket->Data);
pPacket->next = NULL;
push(&pHead, &pPacket);
/*********************************************************
* Display the Link List 'pHead' is passed as a reference *
**********************************************************/
Outpacket(&pHead);
if(pPacket = pop(&pHead))
{
printf("pPacket %s\n", pPacket->Data);
free(pPacket);
};
Outpacket(&pPacket);
while(pPacket = pop(&pHead)) {
free(pPacket);
}
return 0;
}
void Outpacket(node **head)
{
/*********************************************************
* Copy Node pointer so as not to overwrite the pHead *
* pointer *
**********************************************************/
node *pos = *head;
printf("Packet list\n");
/*********************************************************
* Walk the list by following the next pointer *
**********************************************************/
while(pos != NULL) {
printf("Source: %i Destination: %i Type: %i Data: %i \n", pos->Source, pos->Destination, pos->Type, pos->Data, pos->next);
pos = pos->next ;
}
printf("End of Packet\n\n");
}
void push(node **head, node **aPacket)
{
/*********************************************************
* Add the cat to the head of the list (*aCat) allows the *
* dereferencing of the pointer to a pointer *
**********************************************************/
(*aPacket)->next = *head;
*head = *aPacket;
}
node *pop(node **head)
{
/*********************************************************
* Walk the link list to the last item keeping track of *
* the previous. when you get to the end move the end *
* and spit out the last Packet in the list *
**********************************************************/
node *curr = *head;
node *pos = NULL;
if (curr == NULL)
{
return NULL;
} else {
while (curr->next != NULL)
{
pos = curr;
curr = curr->next;
}
if (pos != NULL) // If there are more packets move the reference
{
pos->next = NULL;
} else { // No Packets left then set the header to NULL (Empty list)
*head = NULL;
}
}
return curr;
}
Thanks

Answer 1

#include <stdio.h>
#include <stdlib.h>
#include <conio.h>
struct Packet {
unsigned int Source;
unsigned int Destination;
unsigned int Type;
unsigned int Port;
char *Data;
struct Packet *next;
};
typedef struct Packet* node;
node getnode(void){
node p;
p=malloc(sizeof(struct Packet));/*change1*/
return p;
}
void Outpacket(node *head);
void push(node *head, node *aPacket);/*change 2*/
node pop(node *head);
int main() {
node pPacket = NULL;
node pHead = NULL;
pPacket = getnode();/*change 3*/
if (pPacket == NULL)
{
printf("Error: Out of Memory\n");
exit(1);
}
printf("Enter Source :\n");
scanf("%d", &(pPacket->Source));
printf("Enter Destination Number:\n");
scanf("%d", &(pPacket->Destination));
printf("Enter Type Number:\n");
scanf("%d", &(pPacket->Type));
printf("Enter Port Number:\n");
scanf("%d", &(pPacket->Port));
printf("Enter Data Number:\n");
pPacket->Data=malloc(100);/*change 4,might overflor,so you decide how much memory you want*/
scanf("%s",pPacket->Data);
pPacket->next = NULL;
push(&pHead, &pPacket);
pPacket = getnode();/*change 5*/
if (pPacket == NULL)
{
printf("Error: Out of Memory\n");
exit(1);
}
printf("Enter Source Number:\n");
scanf("%d", &(pPacket->Source));
printf("Enter Destination Number:\n");
scanf("%d", &(pPacket->Destination));
printf("Enter Type Number:\n");
scanf("%d", &(pPacket->Type));
printf("Enter Port Number:\n");
scanf("%d", &(pPacket->Port));
printf("Enter Data Number:\n");
pPacket->Data=malloc(100);/*change 6*/
scanf("%s",pPacket->Data);
pPacket->next = NULL;
push(&pHead, &pPacket);
Outpacket(&pHead);
if(pPacket == pop(&pHead))/*change 7,this was a classic error*/
{
printf("pPacket %s ", pPacket->Data);
free(pPacket);
}
Outpacket(&pPacket);
while(pPacket == pop(&pHead))/*change 8,again the same error,please take care of this*/{
free(pPacket);
}
getch();
return 0;
}
void Outpacket(node *head)
{
node pos = *head;
printf("Packet list\n");
while(pos != NULL) {
printf("Source: %d Destination: %d Type: %d Data: %s \n", pos->Source, pos->Destination, pos->Type,pos->Data);/*change 9,what you wrote was absurd, I think*/
pos = pos->next ;
}
printf("End of Packet\n\n");
}
void push(node *head, node *aPacket)
{
(*aPacket)->next = *head;
*head = *aPacket;
}
node pop(node *head)
{
node curr = *head;
node pos = NULL;
if (curr == NULL)
{
return NULL;
} else {
while (curr->next != NULL)
{
pos = curr;
curr = curr->next;
}
if (pos != NULL)
{
pos->next = NULL;
} else {
*head = NULL;
}
}
return curr;
}
This code runs on my machine perfectly.Please Review the changes and compare both the codes,ask me if you don't understand any change.