파일로부터 단어를 읽어와서 리스트에 저장한 단어장 프로그램인데요 ..

리스트를 처음 써봐서 너무 코드가 복잡한거 같아서 파쟐 여러분께 도움을 얻을까합니다.

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

#define SIZE 26

typedef struct ListNode{
        char word[SIZE];
        struct ListNode *link;
}ListNode;

void error(char *message){
        fprintf(stderr,"%s\n",message);
        exit(1);
}

ListNode *create_node(char *word,ListNode *link){
        ListNode *new_node;
        new_node=(ListNode *)malloc(sizeof(ListNode));
        if( new_node == NULL )
                error("메모리 할당 에러");
        strcpy(new_node->word,word);
        new_node->link=link;
        return (new_node);
}

void insert(ListNode **phead,ListNode **other,ListNode *node,int *num){
        ListNode *p,*q;
        q=node;
        if( *phead == NULL ){
                *phead=node;
                node->link=node;
                (*num)++;
        }
        else{
                p=*phead;
                do{
                        if(strcmp(p->word,q->word)==0){
                                return;
                        }
                        p=p->link;
                }while(p!=*phead);
        }
        p=*other;
        if( *other != NULL){
                do{
                        if(strcmp(p->word,q->word)==0){
                                return;
                        }
                        p=p->link;
                }while(p!=*other);
        }
        
        if( *phead != NULL ){
                node->link=(*phead)->link;
                (*phead)->link=node;
                (*num)++;
        }
}


void display(ListNode *head,int k){
        ListNode *p;
        if( head==NULL )
                return ;
        p=head;
        printf("%c\n",(char)k+65);
        do{
                printf("%s ",p->word);
                p=p->link;
        }while(p!=head);
        printf("\n\n");
}

void search(ListNode *head,ListNode *other,char *searchWord){
        ListNode *p;

        p=head;
        do{
                if(strcmp(p->word,searchWord)==0){
                        printf("단어장에 있습니다.\n");
                        return;
                }
                p=p->link;
        }while(p!=head);
        p=other;
        do{
                if(strcmp(p->word,searchWord)==0){
                        printf("단어장에 있습니다.\n");
                        return;
                }
                p=p->link;
        }while(p!=other);
        printf("단어장에 없습니다.\n");
        return;
}

int main(){
        ListNode *alphabet[SIZE];
        ListNode *theOthers=NULL;

        int choice;
        int i,j,k;
        int num[SIZE];
        char ch;
        char str[SIZE];
        char searchWord[SIZE];

        FILE *file=fopen("c:\\sample.txt","r");
    FILE *file1=fopen("c:\\sample1.txt","w");
    if(file==NULL || file1==NULL){
                printf("file open error!\n");
        return 1;
    }

        while(!feof(file)){
                ch=fgetc(file);
        if(isalpha(ch)==0)
                        ch=' ';
                else
                        ch=toupper(ch);
        fputc(ch,file1);
        }

        fclose(file);
        fclose(file1);

        file1=fopen("c:\\sample1.txt","r");
        if(file1==NULL){
                printf("file1 open error!\n");
                return 1;
        }

        for(i=0;i<26;i++){
                alphabet[i]=NULL;
        }
        for(i=0;i<26;i++){
                num[i]=1;
        }
        
        while(!feof(file1)){
                fscanf(file1,"%s",str);
                k=(int)str[0];
                if(num[k-65]<=6)
                        insert(&alphabet[k-65],&theOthers,create_node(str,NULL),&num[k-65]);
                else
                        insert(&theOthers,&alphabet[k-65],create_node(str,NULL),&num[k-65]);
        }

        fclose(file1);
        
        for(i=0;i<26;i++){
                display(alphabet[i],i);
        }

        display(theOthers,100);

        while(1){
                printf("┌────────────┐\n");
                printf("│기능을 선택하세요       │\n");
                printf("│[1] Search   [2] Insert │\n");
                printf("│[3] Delete   [4] Quit   │\n");
                printf("└────────────┘\n");
                printf(" :");
                scanf("%d",&choice);
        
                switch(choice){
                        case 1:
                                printf("찾을 단어를 입력하세요.: ");
                                scanf("%s",searchWord);
                                for(j=0;j<strlen(searchWord);j++)
                                        searchWord[j]=toupper(searchWord[j]);
                                k=(int)searchWord[0];
                                search(alphabet[k-65],theOthers,searchWord);
                                break;
                        case 2:
                                printf("추가할 단어를 입력하세요.: ");
                                scanf("%s",searchWord);
                                for(j=0;j<strlen(searchWord);j++)
                                        searchWord[j]=toupper(searchWord[j]);
                                k=(int)searchWord[0];
                                if(num[k-65]<=5)
                                        insert(&alphabet[k-65],&theOthers,create_node(searchWord,NULL),&num[k-65]);
                                else
                                        insert(&theOthers,&alphabet[k-65],create_node(searchWord,NULL),&num[k-65]);
                                break;
                }
        }
}


우선 검색,삽입까지는 구현했는데.. 삭제를 구현하는게 힘드네요.

여러번 시도해봤는데 계속 안되서... 어떤방향으로 해야할지 조언을 얻으려고합니다..

코드가 많이 복잡해서 알아보시기 힘드실거 같아 죄송합니다..