Question

• Using the provided Linked List example code, linkedlist.c, as an example

1. Make a node struct that holds ints instead of strings.
2. In your main, insert 25 to 75 random integers with range (0 to 100) into a linked list of your nodes.
   • Use a random to determine how many to make.
3. Write a function int sum(NodePointer current) that returns the sum of the integers in the list by looping through the linked list.
4. Write a function int count(NodePointer current) that returns the number of nodes in the list by looping through the linked list.
5. Use the two functions to calculate the floating point average of the elements
6. Display the contents of the list, the sum, the count, and the average to the screen.

Example I/O

The list is: 0, 0, 1, 4, 5, 6, 8, 9, 12, 13, 14, 17, 19, 20, 20, 23, 24, 25, 25, 26, 28, 30, 30, 32, 34, 36, 37, 38, 43, 44, 46, 50, 53, 54, 54, 62, 62, 65, 66, 66, 68, 70, 70, 74, 79, 79, 80, 82, 83, 85, 85, 89, 96, 97, 
sum = 2338
count = 54
average = 43.30

The list is: 1, 2, 7, 9, 15, 17, 17, 18, 18, 19, 19, 19, 20, 22, 22, 22, 22, 25, 26, 27, 27, 27, 30, 31, 35, 36, 37, 39, 40, 41, 43, 44, 47, 48, 49, 49, 52, 54, 55, 58, 58, 58, 59, 61, 61, 62, 65, 72, 74, 75, 84, 85, 85, 85, 86, 86, 86, 88, 89, 89, 90, 91, 92, 93, 95, 96, 97, 
sum = 3351
count = 67
average = 50.01

The list is: 1, 2, 4, 10, 12, 22, 22, 23, 23, 23, 28, 38, 42, 47, 47, 48, 49, 60, 65, 65, 66, 67, 78, 79, 80, 80, 82, 86, 90, 94, 97, 
sum = 1530
count = 31
average = 49.35

linkedlist.c file

/*
Example of a linked list of strings
*/

#include <stdio.h>
#include <stdlib.h> //has functions malloc() and free()
#include <string.h>
#include "stringinput.h"
#define MAX 30  //maximum characters in the word
#define QUIT "quit" //end the loop

/*
A self-referential structures contains a pointer 
that points to another structure of the same type
and link together to form dynamic data structures.
data: stores a word (string)
next: is a pointer to the next node
*/
struct node{
   char data[MAX];
   struct node *next;
};

//type definition for "new" data types
typedef struct node Node;
typedef struct node* NodePointer;

//function prototypes 
void insertIntoLinkedList(char [], NodePointer *);
void displayLinkedList(NodePointer);
void deleteFromLinkedList(char [], NodePointer *);

/*
main method - asks the user to enter a word,
and inserts the word into a linked list in alphabetical order, 
and deletes words at the user's request.
*/
int main(){
//stores each word
   char word[MAX]={'\0'};
//stores a pointer to the 1st node in the linked list
   NodePointer head = NULL;
   
//keep inserting until user enters "quit"
   while(0 != strcmp(word, QUIT)){
      printf("Enter a word to INSERT into linked list (enter \"%s\" to quit): ", QUIT);
      getline2(word, MAX);
      if(0 != strcmp(word, QUIT)){
      //&head: send the address of the pointer to the 1st node in list
         insertIntoLinkedList(word, &head);
         displayLinkedList(head);
      }
   }//end of while
   
//keep deleting until user enters "quit"
   strncpy(word, "don't quit", MAX);
   printf("\n");
   while(0 != strcmp(word, QUIT) && NULL != head){
      printf("Enter a word to DELETE from linked list (enter \"%s\" to quit): ", QUIT);
      getline2(word, MAX);
      if(0 != strcmp(word, QUIT)){
         deleteFromLinkedList(word, &head);
         displayLinkedList(head);
      }
   }
   
   return 0;
}//end of main

/*
Inserts a word in alphabetical order into a linked list
word2: is a string
head2: is the a pointer to the 1st node in a linked list 
This parameter is a pointer to a pointer, 
because we are passing the address of the linked list to the function, 
and the linked list itself is a pointer to the 1st node in the list.
*/
void insertIntoLinkedList(char word2[], NodePointer *head2){
//pointer to a new node to be inserted into linked list
   NodePointer newNode = NULL;
//pointer to the previous node in the linked list
   NodePointer previous = NULL;
//pointer to the current node in the linked list
   NodePointer current = *head2;

//create a node on the heap
   newNode = malloc(sizeof(Node));
/*
check to see if space is available
if no space on heap, malloc() will return NULL
*/
   if(NULL != newNode){
   //copy over word to the node
      strcpy(newNode->data, word2);
   //figure out where to insert in linked list
      while(NULL != current && strcmp(word2, current->data)>0){
      //move previous to current
         previous = current;
      //move current to next node
         current = current->next;
      }//end of while
      //insert at beginning of linked list
      if(NULL == previous){
         newNode->next = current;
         //change the address stored in head
         *head2 = newNode; 
      }//end of if
      else{
      //insert between previous and current
         previous->next = newNode;
         newNode->next = current;
      }//end of else
   }//end of if
}//end of function


//displays the linked list
void displayLinkedList(NodePointer current){
   //for empty list
   if(NULL == current){
      printf("The linked list is empty!\n\n");
      return;
   }
   printf("linked list items: ");
   //loop through list
   while(NULL != current){
   //display each node
      printf("%s, ", current->data);
      //go to next node
      current = current->next;
   }
   printf("\n\n");
}//end of function


/*
Deletes a word from a linked list
word3: is a string
head3: is the a pointer to the 1st node in a linked list 
This parameter is a pointer to a pointer, 
because we are passing the address of the linked list to the function, 
and the linked list itself is a pointer to the 1st node in the list.
*/
void deleteFromLinkedList(char word3[], NodePointer *head3){
//pointer to a temp node to be deleted from linked list
   NodePointer tempNode = NULL;
//pointer to the previous node in the linked list
   NodePointer previous = NULL;
//pointer to the current node in the linked list
   NodePointer current = *head3;

//check for empty list
   if(NULL == current){
      printf("Cannot delete from empty list!\n");
      return;
   }

/*
check to see if 1st node can be deleted
*/
   if(0 == strcmp(word3, current->data)){
   //get address of 1st node
      tempNode = current;
   //change head to next node
      *head3 = current->next;
   //delete the node
      printf("deleting \"%s\" . . .\n", tempNode->data);
      free(tempNode);
   }
   else{
   //loop through linked list
      while(NULL != current && 0 != strcmp(word3, current->data)){
         //printf("current = %s\n", current->data);
      //move to next node in linked list
         previous = current;
         current = current->next;   
      }//end of while
      if(NULL != current){
      //get current node's address and store in tempNode
         tempNode = current;
         //printf("tempNode = %s\n", tempNode->data);
      //skip over current node
         previous->next = current->next;
      //delete node at current pointer
         printf("deleting \"%s\" . . .\n", tempNode->data);
         free(tempNode);
      }//end of if
   }//end of else    
}//end of function
   

Answer 1

Output:

#include <stdio.h>

#include <stdlib.h>

#include <time.h>

typedef struct Node Node;

struct Node

{

int data;

Node *next;

};

void display(Node *temp)

{

while(temp!=NULL) {

printf("%d, ", temp->data);

temp = temp->next;

}

}

int sum(Node *current)

{

int sm = 0;

while(current!=NULL)

{

sm += current->data;

current = current->next;

}

return sm;

}

int count(Node *current)

{

int ct = 0;

while(current!=NULL)

{

ct++;

current = current->next;

}

return ct;

}

int main()

{

srand(time(0));

int howManyNodes = 25 + rand()%51;

int i;

int totalSum, totalCount;

Node *head = NULL;

for(i=0; i<howManyNodes; i++)

{

if(head == NULL) {

head = (Node*)malloc(sizeof(int));

head->data = rand()%101;

head->next = NULL;

}

else {

Node *temp = head;

Node *newNode = (Node*)malloc(sizeof(int));

newNode->data = rand()%101;

if(newNode->data < head->data) {

newNode->next = head;

head = newNode;

} else {

while(temp->next!=NULL && temp->next->data < newNode->data) {

temp = temp->next;

}

newNode->next = temp->next;

temp->next = newNode;

}

}

}

printf("The list is: ");

display(head);

totalSum = sum(head);

totalCount = count(head);

printf("\nsum = %d\n", totalSum);

printf("count = %d\n", totalCount);

printf("average = %0.2f", totalSum/(float)totalCount);

return 0;

}

#include <stdio.h> #include <stdlib.h> #include <time.h> typedef struct Node Node; struct Node int data; Node *next; void display(Node *temp) while(temp!=NULL) { printf("%d, ", temp->data); temp = temp->next; int sum(Node *current) int sm = 0; while(current!=NULL)

while(current!=NULL) sm += current->data; current = current->next; return sm; int count(Node *current) { int ct = 0; while(current!=NULL) ct++; current = current->next; return ct; int main()

int main() srand(time()); int howManyNodes = 25 + rand()%51; int i; int totalsum, totalCount; Node *head = NULL; for(i=0; i<howManyNodes; i++) if(head == NULL) { head = (Node*)malloc(sizeof(int)); head->data = rand()%101; head ->next = NULL; berpand else { Node *temp = head; while(temp->next != NULL) { temp = temp->next; temp->next = (Node*)nalloc(sizeof(int)); temp = temp->next;

temp->next = (Node*) malloc(sizeof(int)); temp = temp->next; temp->data = rand()%101; temp->next = NULL; printf("The list is: "); display (head); totalsum = sum(head); totalCount = count (head); printf("\nSum = %d\n", totalsum); printf("Count = %d\n", totalCount); printf("Average = %f", totalsum/(float)totalCount); return 0;

The list is: 13, 26, 10, 11, 84, 27, 98, 26, 55, 33, 93, 26, 90, 21, 3, 98, 59, 55, 43, 45, 63, 13 Sum = 1728 Count = 39 Average = 44.307693