I have a homework to write First Come First Serve and Round Robin simulaion and compare them. I started of creating a linked list for making an event list. I have made insert and print_list functions, but couldn't make it work. My friend told me to use Doubly Linked List so I reacreated the linked list and am trying to make print function work. I had a question about my insertion function as I had mistake in order of statements in while loop. After fixing many errors, the print function prints the same node many times, instead of the whole list. I can't which part of the program is wrong. I think that I have error either in insert function and I point pointers wrong, so I get event pointed to itself or I have the error in print function.
When i deleted this line of the code the print function printed only the current node and nothing else.
newpointer->next = *eventlist;
I think that means that I have problem in this part, but I don't get why.
if(prevptr == NULL) //if putting node at the beginning of the list
{
printf("DONEW\n");
newpointer->next = *eventlist;
*eventlist = newpointer;
}
Can you please tell me what's wrong with the code?
#include <stdio.h>
#include <stdlib.h>
struct event {
struct event *next;
int processid;
int arrivaltime;
int cputime;
};
typedef struct event Event;
typedef Event *eventPtr;
Event create_node(int processid, int arrivaltime, int cputime);
void add_event(Event *newpointer, eventPtr *eventlist);
void print_node(Event node);
void print_eventlist(Event *eventlist);
Event get_nextevent(Event *eventlist);
int main(int argc, char* argv[])
{
int sourcenum,a,b,c,i;
Event tempevent;
eventPtr eventlist = NULL;
print_eventlist(eventlist);
char* sources,timeSlice;
if(argc != 3)
printf("Proper usage is: main.c sources time-slice\n");
else
{
sourcenum = atoi(argv[1]);
timeSlice = atoi(argv[2]);
for(i = 0; i < sourcenum ; i++)
{
//print_eventlist(&(*eventlist));
printf("please enter the process-id, arrival-time and cpu-time.\n");
scanf("%d %d %d",&a, &b, &c);
printf("something\n");
tempevent = create_node(a,b,c);
printf("something\n");
add_event(&tempevent, &eventlist);
print_eventlist(eventlist);
}
print_eventlist(eventlist);
}
return 0;
}
void add_event(Event *newpointer, eventPtr *eventlist) //insert
{
printf("DONE1\n");
eventPtr currentptr, prevptr;
printf("DONE2\n");
prevptr = NULL;
printf("DONE3\n");
currentptr = *eventlist;
printf("DONE4\n");
while((currentptr != NULL && currentptr->arrivaltime < newpointer->arrivaltime)) /*on every loop previous and current pointer gets upgraded*/
{
printf("DONEW\n");
prevptr = currentptr;
currentptr = currentptr->next;
}
printf("DONEW\n");
if(prevptr == NULL) //if putting node at the beginning of the list
{
printf("DONEW\n");
newpointer->next = *eventlist;
*eventlist = newpointer;
}
else //putting list between current and previous
{
printf("DONEW\n");
prevptr->next = newpointer;
newpointer->next = currentptr;
}
printf("DONE\n");
}
Event create_node(int processid, int arrivaltime, int cputime)
{
Event *ptr;
ptr = malloc(sizeof(Event));
if(ptr != NULL)
{
ptr->processid = processid;
ptr->arrivaltime = arrivaltime;
ptr->cputime = cputime;
ptr->next = NULL;
}
return *ptr;
}
void print_node(Event node)
{
printf("process-id = %d\n",node.processid);
printf("Arrival Time = %d\n",node.arrivaltime);
printf("CPU time = %d\n",node.cputime);
}
void print_eventlist(eventPtr currentPtr) /*function receives an eventlist and prints all of the events*/
{
if(currentPtr == NULL)
{
puts("List is empty\n");
}
else
{
puts("The List is:");
while(currentPtr != NULL)
{
printf("==========================================\n");//list #%d\n",i);
print_node(*currentPtr);
printf("\n==========================================\n");
currentPtr = currentPtr->next;
}
puts("NULL\n");
}
}
/*int i=0; //This is what I had before
eventPtr currentptr;
*currentptr = *eventlist;
printf("something!!!");
while(currentptr != NULL)
{
i++;
printf("==========================================\nlist #%d\n",i);
print_node(*currentptr);
printf("\n==========================================\n");
currentptr = currentptr->next;
}
}*/
/*Event get_nextevent(Event *eventlist)
{
Event newstruct = create_node(eventlist->processid, eventlist->arrivaltime, eventlist->cputime);
eventlist = eventlist->next;
return newstruct;
}*/
