NetNews Offline 2/NetNews Offline Volume 2.iso/news/comp/lang/c-part2/11600

Text File | 1996-08-05 | 5.5 KB | 253 lines

Path: nntpserver.sp.ac.sg.!usenet
From: ABC <[e-mail]>
Newsgroups: comp.lang.c
Subject: Help on display names
Date: 25 Mar 1996 08:49:45 GMT
Organization: Singapore Polytechnic
Message-ID: <4j5mn9$[e-mail]>
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I need to display a list of names before and after my ADD function
I managed to display a list of names, compute my function, but when i
display the names again, my display function will cock up (display NULL).
Can anyone please give some guidance on this subject?
Thanks


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#include<stdio.h>
#include<alloc.h>
#include<conio.h>
#include<string.h>
#include<ctype.h>
#include<stdlib.h>
#define NSIZE 30     //--array of size to hold name
#define ASIZE 100    //--array of size to hold address
#define FILENAME "B:DATA.DAT"

typedef struct data
{
    char name[NSIZE];
    char address[ASIZE];
    int age;
    struct data *next;
}NodeItem;
typedef NodeItem *Nodeptr;

void menu(void);
void load_record(FILE *fp, Nodeptr *headptr, Nodeptr *lastptr);
void create_link_list(Nodeptr *headptr, Nodeptr *lastptr);
void display_record(Nodeptr *headptr);
void save_record(FILE *fp, Nodeptr *headptr);

int main()
{
     Nodeptr headptr,lastptr;
     char ans1;
     char choice;

     FILE *fp;
     headptr=NULL;
     load_record(fp, &headptr, &lastptr);
     do
     {
      menu();
      choice=getchar();
      choice=toupper(choice);
      flushall();
      switch(choice)
      {
        case 'A': flushall();
              clrscr();
              display_record(&headptr);
              create_link_list(&headptr, &lastptr);
              break;
        case 'B': flushall();
              save_record(fp, &headptr);
              break;
        case 'C': exit(1);
        default : break;
      }
      }while(choice!='C');
      return 0;
}

void menu(void)
{
     printf("\n\nA) ENTER PARTICULAR(S)\n");
     printf("B) SAVE\n");
     printf("C) EXIT\n");
     printf("\nEnter your choice : ");
     return;
}

void create_link_list(Nodeptr *headptr, Nodeptr *lastptr)
{
     int node_size=sizeof(NodeItem);
     Nodeptr ptr;
     char answer='N';

     do
     {
      ptr=(Nodeptr)malloc(node_size);
      printf("\n\nÜÜÜÜÜÜÜÜÜÜ  ENTER PARTICULAR(S)  ÜÜÜÜÜÜÜÜÜÜ\n");
      printf("\nPlease enter name   : ");
      gets(ptr->name);
      if(ptr->name[0]=='0')
      {
           return;
      }
      while(ptr->name[0]=='\0')
      {
           printf("\nPlease enter name   : ");
           gets(ptr->name);
      }
      strcpy(ptr->name, strupr(ptr->name));
      flushall();
      printf("\nPlease enter address : ");
      gets(ptr->address);
      while(ptr->address[0]=='\0')
      {
           printf("\nPlease enter address:");
           gets(ptr->address);
      }
      strcpy(ptr->address,strupr(ptr->address));
      flushall();
      printf("\nPlease enter age :    years old\b\b\b\b\b\b\b\b\b\b\b\b");
      scanf("%d", &(ptr->age));
      while(ptr->age< 1 || ptr->age>100)   //--check for invalid age
      {
           printf("\nPlease enter age :     years old\b\b\b\b\b\b\b\b\b\b\b\b");
           scanf("%d", &(ptr->age));
      }
      flushall();
      if((*headptr)==NULL)
      {
           (*headptr)=ptr;
           (*lastptr)=ptr;
      }
      else
      {
           (*lastptr)->next=ptr;
           (*lastptr)=ptr;
      }
      printf("\nAny more? <Y/N> : ");
      answer=getchar();
      answer=toupper(answer);
      flushall();
     }while(answer!='N');
     (*lastptr)->next=NULL;
     return;
}

void display_record(Nodeptr *headptr)
{
     Nodeptr ptr;
     int y;

     ptr=(*headptr);
     while(ptr!=NULL)
     {
     for(y=1;y<10;y++)
     {
         gotoxy(1,y);printf("%s", ptr->name);
         ptr=ptr->next;
     }
     for(y=1;y<10;y++)
     {
         gotoxy(25,y);printf("%s", ptr->name);
         ptr=ptr->next;
     }
     for(y=1;y<10;y++)
     {
         gotoxy(50,y);printf("%s", ptr->name);
         ptr=ptr->next;
     }
     }
     return;
}

void load_record(FILE *fp, Nodeptr *headptr, Nodeptr *lastptr)
{
     Nodeptr load;
     int node_size=sizeof(NodeItem);
     int name_length,address_length;

     clrscr();
     if((fp=fopen(FILENAME,"r"))==NULL)
     {
      printf("\a\n\nERROR!!!!FILE CAN'T BE OPEN!!!\n");
     }
     else
     {
      while(!feof(fp))
      {
          load=(Nodeptr)malloc(node_size);
          fscanf(fp, "%d\n", &name_length);
          fscanf(fp, "%d\n", &address_length);
          fgets(load->name,name_length+1, fp);
          fscanf(fp,"\n");
          fgets(load->address, address_length+1, fp);
          fscanf(fp, "%d\n",  &load->age);

          if((*headptr)==NULL)
          {
           (*headptr)=load;
           (*lastptr)=load;
          }
          else
          {
           (*lastptr)->next=load;
           (*lastptr)=load;
          }
      }
      (*lastptr)->next=NULL;
     }
     fclose(fp);
     return;
}

void save_record(FILE *fp, Nodeptr *headptr)
{
     Nodeptr save;
     int i;

     if ((fp=fopen(FILENAME,"w"))==NULL)
     {
      printf("\a\n\nERROR!!!!FILE CAN'T BE OPEN!!!\n");
     }
     else
     {
      save=(*headptr);  /****/

      while(save!=NULL)
      {
           fprintf( fp,"%d\n",  strlen(save->name));
           fprintf( fp, "%d\n", strlen(save->address));
           fprintf( fp, "%s\n", save->name);
           fprintf( fp, "%s\n", save->address);
           fprintf( fp, "%d\n", save->age);
           save=save->next;
      }
     }
     fclose(fp);
     printf("\a\n\nSAVING DONE!!!!!\n");
     printf("\nPress any key to continue.....");
     getch();
     return;
}
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