io.h> #include

Please fill in the blanks for C.

/* This program will create a doubly linked list of full names. */

#include<stdio.h>

#include<stdlib.h>

#define LEN 100 //max length

//Declare a node of string that contain a person's full name

// each node has a value and 2 pointers that points to the next node and previous node

struct node

{

       __1__ value[__2__]; //to save the string (full name)

       __3__ __4__ next; //pointer points to next node

       __5__ __6__ prev; //pointer points to previous node

};

/* - This function takes the head pointer and iterates through the list

       to get one full name at a time from the user, and save it to our list

   - The function uses getchar() to get 1 character at a time, and only stops when user presses Enter.

   - During each iteration, check if user inputs a name that is longer than max size.

      + Remember, if maxLen is 100, then the longest valid inputted string len is 98, because 99th index is for null character.

      + So we should stop (invalid) if at any point, the current index reaches index 99, and it's still not the enter key.

   - When done scanning 1 name, make sure to end the string using the pointer.

   - Update the pointer to point to the next node.*/

__7__ scanLL(__8__ __9__  head)

{

       int i;

       while(__10__ __11__ __12__) //this condition makes sure the list is not at the end

       {

              printf("Please put in the name: ");

              char curC = __13__(); //call a function to get a character

              for(i = 0; curC __14__ __15__; i++) //loop runs as long as user hasnt' clicked Enter key

              {

                     //Check if current index is valid, if not, print a message and exit the program

                     if(__16__ == __17__ - __18__)

                     {

                            printf("Your name is too long. Bye\n");

                            __19__;  //terminate the program, no space

                     }

                     __20__ -> __21__ = __22__;// save the character as part of the string, no space

                     curC = __23__(); //call a function to get another character

              }

              __24__ -> __25__ = __26__; //end the current string, no space

              head = __27__; //move to next node, no space

       }

       printf("\n");

}

/*This function prints the list forwards.*/

__28__ printForwards(__29__ __30__ head)

{

       while(__31__ __32__ __33__)//this condition makes sure the list is not at the end

       {

              printf("%s\n", __34__); //print current node's string value, no space

              head = __35__; //move to next node

       }

       printf("\n");

}

//PART 2

/*This function prints the list backwards.*/

__36__ printBackwards(__37__ __38__ head)

{

       while(__39__ __40__ __41__)

       {

              printf("__42__\n", __43__);//print current node's string value

              head = __44__; //move to previous node

       }

       printf("\n");

}

int main()

{

       //PART 1

       //Create 5 character nodes, and link a head pointer to first node.

       __45__ __46__ n1,n2,n3,n4; //nodes

       __47__ __48__ head = __49__;  //head pointer points to first node n1, no spaces

       //Link all nodes to its next, no spaces

       // we'll do in this order n1 -> n2 -> n3 -> n4

       __50__ = __51__; //make a link from n1 to n2

       __52__ = __53__; //make a link from n2 to n3

       __54__ = __55__; //make a link from n3 to n4

       __56__ = __57__; //make a link to show n4 is the end

       scanLL(head); //call the function to scan the strings for our linked list

       printf("\nPrinting back the inputted linked ost:\n");

       printForwards(head); //call the function to print back our list

       //PART 2

       char userIn;

       //Link all nodes to its previous, no spaces

       // n4 -> n3 -> n2 -> n1

       __58__ = __59__; //make a link from n4 to n3

       __60__ = __61__; //make a link from n3 to n2

       __62__ = __63__; //make a link from n2 to n1

       __64__ = __65__; //make a link to show n1 is the end

       //Get a character from user to print (B)ackwards or (F)orward

       printf("Enter F/f to print forward and B/b to print backward: ");

       scanf("%c", &userIn);

       //use switch case to execute accordingly based on user's choice

       switch(__66__)

       {

              case 'F':

              case 'f':

                     head = __67__; //set the head to correct node so it'll print forwards

                     printf("\nPrinting Forwards:\n");

                     printForwards(__68__);

                     break;

              case 'B':

              case 'b':

                     head = __69__;//set the head to correct node so it'll print backwards

                     printf("\nPrinting Backwards:\n");

                     printBackwards(__70__);

                     break;

              default:

                     printf("Invalid input. Bye\n");

                     break;

       }

       return 0;

}