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Displaying Source Code(s)
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To read a phone record Database from File(*.txt)
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Description : The program mainly reads (phone no., person name)
from a txt file (u can add your own elements to make it
comprehensive) and loads it into a LINKED LIST and all file
manipulations are carried over the linked list. Later on, when
the program exits, The changes are reflected back to the file.
Code :
/* PROGRAM TO IMPLEMENT A PHONE RECORD DATABASE USING LINKED
LIST
AND FILE HANDLING USING FORMATTED I/O FUNCTIONS fscanf() and
fprintf()
AUTHOR: JATIN RAJPAL
*/
# include <conio.h>
# include <stdio.h>
# include <alloc.h>
# include <string.h>
struct node
{
int num;
char name[15];
struct node *next;
};
struct node *list; //global start pointer
FILE *fp; // Global file pointer
struct node *getrecord()
{
struct node *temp,e;
temp=(struct node*)malloc(sizeof(struct node));
printf("
Reached till here...");
getch();
fflush(stdin);
// fscanf(fp,"%d %s<BR>,&temp->num,temp->name);
fread(&temp,sizeof(temp),1,fp);
printf("%d %s",temp->num,temp->name);
// temp->num=e.num;
// strcpy(temp->name,e.name);
getch();
temp->next = NULL;
return temp;
}
struct node *getnode()
{
struct node *temp;
temp = (struct node*)malloc(sizeof(struct node));
printf("
Enter the person's phone number--->");
scanf("%d",&temp->num);
printf("
Enter the person's Name--->");
scanf("%s",&temp->name);
temp->next = NULL;
return temp;
}
struct node *search(int id,int *flag)
{
struct node *cur,*prev;
*flag=0;
if
(list==NULL)
return NULL;
for(prev=NULL,cur=list; (cur); prev=cur,cur=cur->next)
if(cur->num == id)
{
*flag = 1;
break;
}
return prev;
}
int insert(struct node *new1)
{
struct node *prev;
int flag;
prev = search(new1->num,&flag);
if(list==NULL)
{
list = new1; //first node in list
return;
}
if(flag==1)
return -1;
else
{
new1->next = prev->next;
prev->next = new1; // insert in the middle or end
}
return 0;
}
void display()
{
struct node *cur;
auto int n=0;
if(list==NULL)
{
printf("
List empty !");
return;
}
printf("
The phone records are---><BR>);
cur=list;
for(cur=list;(cur);cur=cur->next)
{
printf("
Record no. %d---><BR>,n+1);
printf("
Record phone no.:%d",cur->num);
printf("
person Name:%s
<BR>,cur->name);
n++;
}
}
int delnode(int id)
{
struct node *prev,*temp;
int flag=0;
if(list==NULL)
return -1;
prev=search(id,&flag);
if(flag==0)
return -1;
if(prev==NULL)
{
temp=list;
list=list->next;
free(temp);
}
else
{
temp=prev->next;
prev->next=temp->next;
free(temp);
}
return 0;
}
struct node *query(int id,char *flag,int toggle)
{
struct node *cur,*prev;
int x=0;
if(list==NULL)
return NULL;
if(toggle)
{
for(prev=NULL,cur=list; (cur); prev=cur,cur=cur->next)
if(cur->num == id)
{
x=1;
break;
}
}
else
{
for(prev=NULL,cur=list; (cur); prev=cur,cur=cur->next)
if(!strcmp(cur->name,flag))
{
x=1;
break;
}
}
if(x==0)
{
printf("
The number doesnt exist !");
return NULL;
}
return cur;
}
void CopyToFile()
{
FILE *fp;
struct node *cur;
fp=fopen("phone.txt","w");
cur=list;
if(cur==NULL)
{
printf("
The list is empty, nothing to write back...");
return;
}
for(cur=list;(cur);cur=cur->next)
fprintf(fp,"%d %s<BR>,cur->num,cur->name); //writing back to
file
fclose(fp);
}
void main()
{
int ch=0,ans=0;
int val=0;
char str[15];
struct node *new1,*new2;
clrscr();
/* initialization of list with the existing records */
fp=fopen("phone.txt","r");
if(fp==NULL)
{
printf("
File cant be opened !");
getch();
exit(1);
}
while(!feof(fp))
{
new1=getrecord();
if(insert(new1)==-1)
printf("
Cant insert record ! Error...");
else
printf("
Record entered...");
}
getch();
fclose(fp);
do
{
clrscr();
printf("
Menu");
printf("
1. Add a New phone record.");
printf("
2. Delete an existing Record.");
printf("
3. show all Records.");
printf("
4. Modify a particular Record.");
printf("
5. Exit.");
printf("
Enter your choice--->");
scanf("%d",&ch);
switch(ch)
{
case 1:
new1 = getnode();
val = insert(new1);
if(val==-1)
printf("
Employee id already exists ! try again...");
else
printf("
Employee details successfully stored");
break;
case 2:
printf("
Enter the phone no.you wish to delete--->");
scanf("%d",&val);
ans=delnode(val);
if(ans==-1)
printf("
Record doesnt exist ! Try again...");
if(ans==0)
printf("
Record deleted !");
break;
case 3:
display();
break;
case 4:
printf("
Search by phone no. or Name ? (1/2)--->");
scanf("%d",&ch);
if(ch==1)
{
printf("
Enter the phone no. you wish to search for--->");
scanf("%d",&val);
new2=query(val,&str,1);
}
else
{
printf("
Enter the name of the person you wish to search
for--->");
scanf("%s",&str);
new2=query(val,&str,0);
}
if(new2)
{
printf("
Enter the New name of the person--->");
scanf("%s",&new2->name);
printf("
Enter new phone no. of the person--->");
scanf("%d",&new2->num);
printf("
Record modified successfully !");
}
break;
case 5:
printf("
Leaving Database,writing back to file...");
CopyToFile();
getch();
free(list);
exit(1);
break;
}
getch();
}while(1);
}
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123
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