print the data by order (i.e by last name)

Hi,

I am having this problem about printing data by order, a user should be prompted to list the data by last name, first name, party or votes. Here is the code:
INSERT

Code:

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#include <stdio.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>

/*********************************/
/* structure EastDevon*/

struct EastDevon {
    char party[2];
    char lastName[31];
    char firstName[31];
    unsigned int votes[4];
    struct EastDevon *nextresult;
    };
typedef struct EastDevon RESULT;

/* function prototypes */

RESULT ProcessFile (FILE *);
void AddResult    (RESULT *, char*, char *, char *, unsigned int, unsigned int, unsigned int, unsigned int);
void PrintList (RESULT *);

/* main function */

int main() {
    FILE *fin;
    RESULT root;
    if ((fin = fopen("EastDevon.txt", "r")) == NULL)
    {
    printf ("Unable to read file\n");
    return EXIT_FAILURE;
    }
   
    root = ProcessFile(fin);
    PrintList(&root);
   
    fclose(fin);
    return EXIT_SUCCESS;
}

/*Reads the file pointed to by fin and constructs a linked list structure,
/* with root as the root result of the tree;    */

RESULT ProcessFile (FILE *fin){
    RESULT root;
    char cParty[2];
    char cLastName[31];
    char cFirstName[31];
    unsigned int C1Votes;
    unsigned int C2Votes;
    unsigned int C3Votes;
    unsigned int C4Votes;
    int count = 0;
   
    while (fscanf (fin, "%s%s%s%d%d%d%d", cParty, cLastName, cFirstName, &C1Votes, &C2Votes, &C3Votes, &C4Votes) == 4)
  {
    count++;
    if (count == 1)
    {
        strcpy(root.party, cParty);
        strcpy(root.lastName, cLastName);
        strcpy(root.firstName, cFirstName);
        root.votes[0]= C1Votes;
        root.votes[1]=C2Votes;
        root.votes[2]=C3Votes;
        root.votes[3]=C4Votes;
        root.nextresult = NULL; }
    else
      AddResult (&root, cParty, cLastName, cFirstName, C1Votes,C2Votes,C3Votes,C4Votes);
  }
    return root;
}


/*Add a new result to the linked list whose root result is in the first
/*parameter passed to the function    */


void AddResult  (RESULT *root,
        char *cParty,
        char *cLastName,
        char *cFirstName,
        unsigned int C1Votes,
        unsigned int C2Votes,
        unsigned int C3Votes,
        unsigned int C4Votes)
{
    RESULT *result = root;
    RESULT *newresult = (RESULT *)malloc(sizeof(RESULT));
   
    if (newresult == NULL)
    {
        printf("Unable to allocate memory\n");
        exit(EXIT_FAILURE);
    }
   
    strcpy(newresult->party, cParty);
    strcpy(newresult->lastName, cLastName);
    strcpy(newresult->firstName, cFirstName);
    newresult->votes[0] = C1Votes;
    newresult->votes[1]=C2Votes;
    newresult->votes[2]=C3Votes;
    newresult->votes[3]=C4Votes;

    newresult->nextresult = NULL;
   
    while (result->nextresult !=NULL)
        result = result->nextresult;
   
    result->nextresult = newresult;
}

/* print all the results in the linked list */


void PrintList (RESULT *result)
{
    if (result == NULL)
    return;
   
    printf("%s:%s:%s:%08d\n", result->party, result->lastName,
          result->firstName, result->votes[0], result->votes[1], result->votes[2], result->votes[3]);
 
    PrintList(result->nextresult);
}

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Now the program should Prompt the user to select which order they wish to see the results in. (i.e last name)


I do not know how to start this, would be very thankful, if u could help.