Singly Linked List

/**
    Program Name: Singly Linked List

    Description: This Program is for Implemeting Singly Linked List

    Author:  Tauqirul Haque
       
*/


struct Linklist
{
    int item;
    struct Linklist *next;
};

typedef struct Linklist node;

void insertAtBeginning(node **);
void createAppendNode(node **);
void insertInMiddle(node **);
void deleteNode(node **);
void displayNode(node **);
void countNode(node **); 
void searchElement(node **);
void reverse(node **);


void main()
{
    node *head = NULL;
    int choice = 0;
    while(choice != 9)
    {
       
    printf("\n\t\t\t1. Add Node At The Beginning ");
    printf("\n\t\t\t2. Insert Element in the Middle ");
    printf("\n\t\t\t3. Append New Node ");
    printf("\n\t\t\t4. Delete Node ");
    printf("\n\t\t\t5. Display Node ");
    printf("\n\t\t\t6. Count Nodes ");
    printf("\n\t\t\t7. Search Element ");
    printf("\n\t\t\t8. Reverse The List");
    printf("\n\t\t\t9. Exit Program ");
    printf("\n Enter Your Choice #  ");
   
    scanf("%d",&choice);
   
    switch(choice)
    {
        case 1:
                  insertAtBeginning(&head);
                  break;
         case 2:
                 insertInMiddle(&head);
                 break;
        case 3:
                createAppendNode(&head);
                break;               
        case 4:
                deleteNode(&head);
                break;
        case 5:
                displayNode(&head);
                break;
        case 6:
                countNode(&head);
                break;
        case 7:
                searchElement(&head);
                break;
        case 8:
                reverse(&head);
                break;
               
        case 9:
                printf("\n\nProgram Terminating ... \n");
                exit(0);
    }
    }
}

void createAppendNode(node **head)
{
    int data;
    printf("Enter The Data  #  ");
    scanf("%d",&data);
   
    node *temp, *newNode;  //temp is just for temporarily getting head address and newNode for inserting new node
   
    temp = *head;  //storing head's address
   
    if(*head == NULL)    //if no node then;
    {
        temp = (node *)malloc(sizeof(node));  //allocating memory for temp
        temp->item = data;
        temp->next = NULL;
        *head = temp;   //now storing the value of temp in head,, head is the first node
    }
    else
    {
        temp = *head;
        while(temp->next != NULL)   //moving to the last node
        {
            temp = temp->next;
        }
       
        newNode = (node *)malloc(sizeof(node ));  //allocating memory for the new node
       
        newNode->item = data;  //assigning value to newNode
        newNode->next = NULL; //assigning  NULL to the address of newNode
       
        temp->next = newNode;   //now the old list points to the newly created node;
    }
}

void displayNode(node **head)
{

    node *temp = *head;

    if(temp == NULL)    //checking if the list is empty then printing No elements to display
    {
        printf("\n\nThe List is EMPTY!!!\n\n");
        return;
    }

    printf("\n\nThe Elements of the List are #  ");

    while(temp != NULL)        //running the loop till the end to display every element
    {
        printf("%4d",temp->item);
        temp = temp->next;
    }
    printf("\n\n");
}


void deleteNode(node **head)
{
    node *temp, *previousNode; //previousNode will hold the address of previous node
    int data;
    int flag = 0; //assuming the element is not in the list
   
    temp = *head;
   
    if(temp == NULL)
    {
        printf("\n\n List EMPTY!!! .. No Element To Be Deleted \n\n");
        return;
    }
    printf("\n\nEnter The Element To Be Deleted  #  ");
    scanf("%d",&data);
   
    while(temp != NULL)
    {
        if(temp->item == data)
        {
            if(temp == *head)  //checking for the first node
            {
                *head = temp->next;    //shifting the head address to the next node
            }
            else
            {
                previousNode->next = temp->next;  //storing the address of previous node
            }
           
            flag = 1;  //item found
           
            free(temp);    //releasing the memory
        }
        else
        {
            previousNode = temp;
            temp = temp->next;
        }
    }
       
        if(flag==1)
        {
            printf("\n\nThe Element %d was Successfully DELETED \n\n",data);
        }
        else
        {
            printf("\n\nThe Element %d is NOT in The List \n\n",data);
        }   
}


void countNode(node **head)
{
    int count = 0;
    node *temp = *head;
   
    if(temp == NULL)
    {
        printf("\n\nList Empty ... No Elements\n\n");
    }
    else
    {
        while(temp != NULL)
        {
            count++;
            temp = temp->next;
        }
       
        printf("\n\nTotal Nodes #  %d ",count);
    }
}


void insertAtBeginning(node **head)
{
    node *temp;    //this will be our new node
    int data;
   
    printf("\n\nEnter The Element You Want To Insert  #  ");
    scanf("%d",&data);
   
    temp = (node *)malloc(sizeof(node));
   
    if(temp == NULL)
    {
        printf("\n\n No Memory Available .... OVERFLOW \n\n");
        return;
    }
   
    temp->item = data ; //assigning the element
    temp->next = *head; //now this will point to the head node as this will be the first element
   
    *head = temp;  //now making head point to this node
}

void insertInMiddle(node **head)
{
    node *newNode;
    node *temp = *head;
    int data;
    int count = 1;
    int flag = 0; 
    int location;
   
    if(temp == NULL)
    {
        printf("\n\nList Empty ... Cannot Insert \n\n");
        return;
    }
   
    printf("\n\nEnter The Location Where You Want to Insert New Node  # ");
    scanf("%d",&location);
    printf("\nEnter The Element You Want To Insert #  ");
    scanf("%d",&data);
   
    newNode = (node *)malloc(sizeof(node));
   
    if(newNode == NULL)
    {
        printf("\n\nMemory Full...OVERFLOW !!! \n\n");
        return;
    }
   
    while(temp != NULL)
    {
        if(count == location)
        {
            newNode->item = data;
            newNode->next = temp->next;
           
            temp->next = newNode;
            flag = 1;
        }
       
        temp = temp->next;
        count++;
    }
   
    if(flag == 1)
    {
        printf("\n\nNode Inserted Successfully ... \n\n");
    }
    else
    {
        printf("\n\nSpecified Location Does Not Exits ..\n\n");
    }
}

void searchElement(node **head)
{
    node *temp = *head;
    int item;
    int location = 1;
   
    printf("\n\nEnter The Element To Be Searched #  ");
    scanf("%d",&item);
   
    while(temp != NULL)
    {
        if(temp->item == item)
        {
            printf("\n\nSearch Successfull.. Element Found At Location %d \n\n", location);
            return;
        }
       
        location++;
       
        temp = temp->next;
    }
   
    printf("\n\nSearch UNSUCCESSFULL !!!... Element Not In The List\n\n");
}     

void reverse(node **head)
{
    node *tempHead = *head;
    node *reverseNode = NULL;
    node *swapper;
   
    while(tempHead)   //this loops runs while the value of tempHead is not NULL
    {
        swapper = reverseNode;  //doing the swapping job
        reverseNode = tempHead;
        tempHead = tempHead->next;
        reverseNode->next = swapper;
    }
   
    *head = reverseNode;  //now making the head point to the reversed list
}