Please finish the int LLInsert function. typedef struct STUDENT { char *Netid; i
ID: 3781740 • Letter: P
Question
Please finish the int LLInsert function.
typedef struct STUDENT
{
char *Netid;
int Midterm;
int Final;
} STUDENT;
typedef char* LLKey;
typedef STUDENT LLValue;
typedef struct LLNode
{
LLKey Key;
LLValue Value;
struct LLNode *Next;
} LLNode;
typedef struct LL
{
LLNode *Head;
int Count;
} LL;
//
// LLCreate: dynamically creates and returns an empty linked-list:
//
LL *LLCreate()
{
LL *list;
list = (LL *) malloc(sizeof(LL));
list->Head = NULL;
list->Count = 0;
return list;
}
//
// LLCompareKeys: compares key1 and key2, returning
// value < 0 if key1 < key2
// 0 if key1 == key2
// value > 0 if key1 > key2
//
int LLCompareKeys(LLKey key1, LLKey key2)
{
// NOTE: with STUDENTs, keys are Netids, so use strcmp.
if (strcmp(key1, key2) < 0)
return -1;
else if (strcmp(key1, key2) == 0)
return 0;
else
return 1;
}
//
// LLInsert: inserts the given (key, value) pair into the linked-list such
// that the new key is in ascending order with respect to the other keys.
// Returns true (non-zero) if the insert was successful, returns false (0)
// if the given key is already in the list -- and the given (key, value)
// pair is not inserted.
//
int LLInsert(LL *list, LLKey key, LLValue value)
{
return 1; // insert was successful:
}
// inputs and discards the remainder of the current line for the
// given input stream, including the EOL character(s):
void skipRestOfInput(FILE *stream)
{
char restOfLine[256];
int rolLength = sizeof(restOfLine) / sizeof(restOfLine[0]);
fgets(restOfLine, rolLength, stream);
}
int main(int argc, char *argv[])
{
char netid[16];
int mid, fnl, added;
STUDENT s;
LL *list = LLCreate();
LLNode *cur = NULL;
memdebug_init(0); // 1 => interactive; switch to 0 inside zyLabs
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
while (netid[0] != '#')
{
s.Netid = (char *)malloc((strlen(netid)+1) * sizeof(char));
strcpy(s.Netid, netid);
s.Midterm = mid;
s.Final = fnl;
// add to end of list:
LLNode *node;
node = (LLNode *) malloc(sizeof(LLNode));
node->Key = s.Netid;
node->Value = s;
node->Next = NULL;
if (cur == NULL) // first time:
{
list->Head = node;
cur = node;
}
else // new node follows current:
{
cur->Next = node;
cur = node;
}
list->Count++;
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
}
//
// now call insert function to see if it works:
//
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
s.Netid = (char *)malloc((strlen(netid) + 1) * sizeof(char));
strcpy(s.Netid, netid);
s.Midterm = mid;
s.Final = fnl;
added = LLInsert(list, s.Netid, s);
if (!added)
{
printf("**not inserted** ");
}
else
{
printf("**inserted** ");
}
// output contents of list:
printf(">>Count=%d ", list->Count);
cur = list->Head;
while (cur != NULL)
{
printf(">>%s: %d,%d ", cur->Value.Netid, cur->Value.Midterm, cur->Value.Final);
cur = cur->Next;
}
return 0;
}
Explanation / Answer
PROGRAM CODE:
#include <stdio.h>
#include<string.h>
#include<malloc.h>
typedef struct STUDENT
{
char *Netid;
int Midterm;
int Final;
} STUDENT;
typedef char* LLKey;
typedef STUDENT LLValue;
typedef struct LLNode
{
LLKey Key;
LLValue Value;
struct LLNode *Next;
} LLNode;
typedef struct LL
{
LLNode *Head;
int Count;
} LL;
//
// LLCreate: dynamically creates and returns an empty linked-list:
//
LL *LLCreate()
{
LL *list;
list = (LL *) malloc(sizeof(LL));
list->Head = NULL;
list->Count = 0;
return list;
}
//
// LLCompareKeys: compares key1 and key2, returning
// value < 0 if key1 < key2
// 0 if key1 == key2
// value > 0 if key1 > key2
//
int LLCompareKeys(LLKey key1, LLKey key2)
{
// NOTE: with STUDENTs, keys are Netids, so use strcmp.
if (strcmp(key1, key2) < 0)
return -1;
else if (strcmp(key1, key2) == 0)
return 0;
else
return 1;
}
//
// LLInsert: inserts the given (key, value) pair into the linked-list such
// that the new key is in ascending order with respect to the other keys.
// Returns true (non-zero) if the insert was successful, returns false (0)
// if the given key is already in the list -- and the given (key, value)
// pair is not inserted.
//
int LLInsert(LL *list, LLKey key, LLValue value)
{
LLNode *node = (LLNode *) malloc(sizeof(LLNode));
node->Key = key;
node->Value = value;
node->Next = NULL;
LLNode *temp = list->Head;
while(temp != NULL)
{
if(LLCompareKeys(temp->Key, key)==0)
{
return 0;
}
temp = temp->Next;
}
if(list->Head == NULL)
{
list->Head = node;
}
else
{
LLNode *cur = list->Head;
while(cur->Next != NULL)
{
if(LLCompareKeys(cur->Key, key)==1)
{
LLNode *temp =(LLNode *) malloc(sizeof(LLNode));
temp->Key = cur->Key;
temp->Value = cur->Value;
temp->Next = cur->Next;
cur->Key = key;
cur->Value = value;
cur->Next = temp;
list->Head = cur;
return 1;
}
cur = cur->Next;
}
}
return 1; // insert was successful:
}
// inputs and discards the remainder of the current line for the
// given input stream, including the EOL character(s):
void skipRestOfInput(FILE *stream)
{
char restOfLine[256];
int rolLength = sizeof(restOfLine) / sizeof(restOfLine[0]);
fgets(restOfLine, rolLength, stream);
}
int main(int argc, char *argv[])
{
char netid[16];
int mid, fnl, added;
STUDENT s;
LL *list = LLCreate();
LLNode *cur = NULL;
//memdebug_init(0); // 1 => interactive; switch to 0 inside zyLabs
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
while (netid[0] != '#')
{
s.Netid = (char *)malloc((strlen(netid)+1) * sizeof(char));
strcpy(s.Netid, netid);
s.Midterm = mid;
s.Final = fnl;
// add to end of list:
LLNode *node;
node = (LLNode *) malloc(sizeof(LLNode));
node->Key = s.Netid;
node->Value = s;
node->Next = NULL;
if (cur == NULL) // first time:
{
list->Head = node;
cur = node;
}
else // new node follows current:
{
cur->Next = node;
cur = node;
}
list->Count++;
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
}
//
// now call insert function to see if it works:
//
scanf("%s %d %d", netid, &mid, &fnl);
skipRestOfInput(stdin);
s.Netid = (char *)malloc((strlen(netid) + 1) * sizeof(char));
strcpy(s.Netid, netid);
s.Midterm = mid;
s.Final = fnl;
added = LLInsert(list, s.Netid, s);
//added = 1;
if (!added)
{
printf("**not inserted** ");
}
else
{
printf("**inserted** ");
}
// output contents of list:
printf(">>Count=%d ", list->Count);
cur = list->Head;
while (cur != NULL)
{
printf(">>%s: %d,%d ", cur->Value.Netid, cur->Value.Midterm, cur->Value.Final);
cur = cur->Next;
}
return 0;
}
INPUT:
ASD234 23 34
ASD233 23 34
ASD234 23 34
#ASD235 2 3
OUTPUT: