Linkes list progam in C won't save the student information entered. It only displays the last pieces of information entered by the user. Could someone please help?

Here is the code --

#include #include #include

typedef struct studentNode { char firstName[20]; char lastName[20]; unsigned int studID; char major[30]; double gpa; struct studentNode *nextPtr; } studentNode_t;

void insertNode(studentNode_t **ptrToHeadPtr, const studentNode_t *a, const studentNode_t *b, char lname[20] ); void printList(studentNode_t *headPtr);

int main(void) { int count = 0;

studentNode_t *tmp = NULL; tmp =(struct studentNode *)malloc(sizeof(studentNode_t));

do {

if (count == 0) { printf("Enter the first student's first name or -1 to end input: "); scanf("%s", tmp->firstName); } else { printf("Enter the next student's first name or -1 to end input: "); scanf("%s", tmp->firstName); } if (strcmp(tmp->firstName, "-1") != 0) {

printf("Enter the student's last name: "); scanf("%s", tmp->lastName); printf("Enter the student's ID number: "); scanf("%u", &(tmp->studID)); printf("Enter the student's major: "); scanf("%s", tmp->major); printf("Enter the student's gpa: "); scanf("%lf", &(tmp->gpa));

} count++; }while (strcmp(tmp->firstName, "-1") != 0); printList(tmp); return (0); }

void insertNode(studentNode_t **ptrToHeadPtr, const studentNode_t *a, const studentNode_t *b, char lname[20]) {

studentNode_t *newNodePtr = (studentNode_t *)malloc(sizeof(studentNode_t));

if (newNodePtr != NULL) { strcpy(newNodePtr->lastName, lname); // Place value in node

newNodePtr->nextPtr = NULL; // Node is not linked to another node

studentNode_t *prevPtr = NULL;

studentNode_t *currPtr = *ptrToHeadPtr;

while (currPtr != NULL && (strcmp(a->lastName, b->lastName)< 0)) {

prevPtr = currPtr;

currPtr = currPtr->nextPtr; }

if (strcmp(a->lastName,b->lastName) == 0) { while (currPtr != NULL && (strcmp(a->firstName, b->firstName) < 0)) {

prevPtr = currPtr;

currPtr = currPtr->nextPtr; }

}

if (NULL == prevPtr) // Inserting at the beginning of list { newNodePtr->nextPtr = *ptrToHeadPtr; *ptrToHeadPtr = newNodePtr; } else {

prevPtr->nextPtr = newNodePtr;

newNodePtr->nextPtr = currPtr; } }

return; } // End of insertNode function

void printList(studentNode_t *headPtr) { studentNode_t *tmp = headPtr; puts(" NAME OF STUDENT\t\t\tSTUDENT ID\tMAJOR\t\t\tGPA ");

while (tmp != NULL) { printf("%s %s\t\t\t%d\t\t%s\t\t\t%.2f ",tmp->firstName, tmp->lastName, tmp->studID, tmp->major, tmp->gpa); tmp = tmp -> nextPtr; }

return; }

**It should run and look just like this :

Enter the next student's first name or -1 to end input: Katherine

Enter the student's last name: Watson

Enter the student's ID number: 2016112345

Enter the student's major: Mechanical Engineering

Enter the student's gpa: 3.2

Enter the next student's first name or -1 to end input: Daniel

Enter the student's last name: Grimes

Enter the student's ID number: 2016412412

Enter the student's major: Computer Science

Enter the student's gpa: 2.87

Enter the next student's first name or -1 to end input: Trent

Enter the student's last name: Newsom

Enter the student's ID number: 2016521245

Enter the student's major: Mechanical Engineering

Enter the student's gpa: 3.3

Enter the next student's first name or -1 to end input: -1

NAME OF STUDENT STUDENT ID MAJOR GPA

Daniel Grimes 2016412412 Computer Science 2.87

Trent Newsom 2016521245 Mechanical Engineering 3.30

Katherine Watson 2016112345 Mechanical Engineering 3.20

I really just need help keeping all the data entered.