/*Title : Creating Student Database Using Singly linked list */
#include<stdio.h>
#include<conio.h>
struct Student
{
int roll;
char name[30];
float marks;
struct Student *next; //Self referential pointer...
};
typedef struct Student Node;
void Linkfloat()
{
float a=0,*b; //To create link of float to some compiler ...
b=&a;
a=*b;
}
void Display(Node *head)
{
Node *p;
int i;
if(head==NULL)
{
printf("
There is no records in database.
");
}
else
{
p=head;
for(i=0;i<80;i++)
{
printf("-");
}
printf("
Updated Student Database
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
printf("Roll No. Name Marks
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
while(p!=NULL)
{
printf("%d %s %0.2f",p->roll,p->name,p->marks);
printf("
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
flushall();
p=p->next; //Go to next node...
}
}
}
void DReverse(Node * head)
{
Node *p;
int i;
if(head==NULL)
{
printf("
There is no records in database.
");
}
else
{
p=head;
if(p->next!=NULL)
{
DReverse(p->next); //Recursive call...
}
printf("%d %s %0.2f",p->roll,p->name,p->marks);
printf("
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
flushall();
printf("
");
}
}
Node* Create(Node *head)
{
int n,i;
Node *nn,*p;
printf("
How many Entries to Create Database???
");
scanf("%d",&n);
for(i=0;i<n;i++)
{
if(head==NULL)
{
nn=(Node*)malloc(sizeof(Node)); //Creating first node...
printf("
Enter Roll No. , Name & Marks
");
scanf("%d",&(nn->roll));
flushall();
gets(nn->name);
scanf("%f",&(nn->marks));
nn->next=NULL; //Set next to NULL...
head=nn;
}
else
{
p=nn=head;
while(nn->next!=NULL)
{
nn=nn->next;
}
nn->next=(Node*)malloc(sizeof(Node)); //Creating further nodes...
nn=nn->next;
printf("
Enter Roll NO.,Name & Marks
");
scanf("%d",&(nn->roll));
flushall();
gets(nn->name);
scanf("%f",&(nn->marks));
nn->next=NULL;
nn=p;
}
}
return head;
}
Node* Insert(Node *head)
{
int ch,r;
char ans;
Node *p,*nn,*q;
do
{
printf("
Whwre do you want to enter new entry???
");
printf("
1.At the Begining
2.At the middle
3.At the end
");
printf("
Enter your choice:
");
scanf("%d",&ch);
switch(ch)
{
case 1:
/* Insert at Begining */
p=head;
nn=(Node*)malloc(sizeof(Node));
printf("
Enter Roll NO., Name & Marks
");
scanf("%d",&(nn->roll));
flushall();
gets(nn->name);
scanf("%f",&(nn->marks));
nn->next=NULL;
nn->next=p;
head=nn; //set first node as head...
printf("
Entry is Created successfully.
");
Display(head);
break;
case 2:
/* Insert at Middle */
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
}
else
{
printf("
After which Roll NO. You want to insert new Data???
");
scanf("%d",&r);
p=head;
while(p->roll!=r && p->next!=NULL)
{
p=p->next; //Go upto that roll no....
}
if(p->roll!=r)
{
printf("
There is no such entry.
");
}
else
{
nn=(Node*)malloc(sizeof(Node));
printf("
Enter Roll NO.,Name & Marks
");
scanf("%d",&(nn->roll));
flushall();
gets(nn->name);
scanf("%f",&(nn->marks));
nn->next=NULL;
q=p->next;
p->next=nn;
nn->next=q;
printf("
Entry is Created successfully.
");
Display(head);
}
}
break;
case 3:
/* Insert at end */
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
}
else
{
p=head;
nn=(Node*)malloc(sizeof(Node));
printf("
Enter Roll NO.,Name & Marks
");
scanf("%d",&(nn->roll));
flushall();
gets(nn->name);
scanf("%f",&(nn->marks));
nn->next=NULL;
while(p->next!=NULL)
{
p=p->next; //Go upto last node...
}
p->next=nn;
printf("
Entry is Created successfully.
");
Display(head);
}
break;
}
printf("
Do you want to Insert more data(Y/N)???");
flushall();
scanf("%c",&ans);
}while(ans=='y' ans=='Y');
return head;
}
Node* Delete(Node* head)
{
Node *p,*q,*r;
char ans;
int ch,n;
do{
printf("
Which Entry you want to Delete???
");
printf("
1.First
2.Middle
3.End
");
scanf("%d",&ch);
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
}
else
{
switch(ch)
{
case 1:
/*Delete first node */
p=head;
head=head->next; //Set second node as head...
free(p);
printf("
First entry is deleted.
");
Display(head);
break;
case 2:
/*Delete middle Node*/
p=head;
printf("
Enter roll no. which you want to delete:
");
scanf("%d",&n);
while((p->next)->roll!=n && p->next->next!=NULL)
{
p=p->next; //Go upto -1 node which you want to delete...
}
if(p->next->next==NULL)
{
printf("
There is no such entry.
");
}
else
{
q=p->next;
r=q->next;
p->next=r;
free(q); //Delete that node...
printf("
Entry is deleted.
");
Display(head);
}
break;
case 3:
/* Delete last node */
p=head;
while(p->next->next!=NULL)
{
p=p->next; //Go upto -1 node which you want to delete...
}
q=p->next;
free(q); //Delete last node...
p->next=NULL;
printf("
Last entry is deleted.
");
Display(head);
break;
}
}
printf("
Do you want to delete more data(Y/N)???
");
flushall();
scanf("%c",&ans);
}while(ans=='y' ans=='Y');
return head;
}
Search(Node *head)
{
Node *p;
int r,cnt=0;
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
}
else
{
p=head;
printf("
Enter roll no. which you want to Search:
");
scanf("%d",&r);
while(p->roll!=r && p->next!=NULL) //Search for roll no...
{
p=p->next;
cnt++;
}
if(p->roll!=r)
printf("
There is no such entry.
");
else
{
printf("
Roll NO. %d is at %d th Position.",r,(cnt+1));
printf("
Roll No. Name Marks
");
printf("%d %s %0.2f",p->roll,p->name,p->marks);
}
}
}
Modify(Node * head)
{
Node *p;
int r;
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
}
else
{
p=head;
printf("
Enter the Roll no. whose data you want to modify:
");
scanf("%d",&r);
while(p->roll!=r && p->next!=NULL)
{
p=p->next;
}
if(p->roll!=r)
{
printf("
Thre is no such record in Database.
");
}
else
{
printf("
Entered roll no's Data is:
");
printf("Roll No. Name Marks
"); //Displaying Data who is going to modify....
printf("%d %s %f",p->roll,p->name,p->marks);
printf("
Enter New roll no ,New name & Marks for this entry:
");
scanf("%d",&p->roll);
flushall();
gets(p->name); //Enter new data...
scanf("%f",&(p->marks));
printf("
Entered New Data is:
");
printf("Roll No. Name Marks
");
printf("%d %s %f",p->roll,p->name,p->marks);
Display(head);
}
}
}
Count(Node *head)
{
Node *p;
int cnt=0;
if(head==NULL)
{
printf("
Yet database is not created.");
printf("
Database is empty.
");
printf("
First Create Database.
");
printf("
There are 0 records in Database.
");
}
else
{
p=head;
while(p->next!=NULL)
{
p=p->next;
cnt++; //Counting records...
}
printf("
There are %d records in Database.
",(cnt+1));
}
}
void main()
{
int ch,i;
char op;
Node *head;
head=NULL;
printf("
*----------Studednt Database-----------*
");
do
{
printf("
Menu
1.Create Database
2.Insert
3.Delete
4.Search
5.Modify
6.Display
7.Display Reverse
8.Count Records
9.Exit
");
printf("
Enter your choice
");
scanf("%d",&ch);
switch(ch)
{
case 1:
head=Create(head); //Call to Create...
break;
case 2:
head=Insert(head); //Call to Insert...
break;
case 3:
head=Delete(head); //Call to Delete...
break;
case 4:
Search(head); //Call to Search...
break;
case 5:
Modify(head); //Call to Modify...
break;
case 6:
Display(head); //Call to Display...
break;
case 7:
for(i=0;i<80;i++)
{
printf("-");
}
printf("
Updated Student Database
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
printf("Roll No. Name Marks
");
for(i=0;i<80;i++)
{
printf("-");
}
printf("
");
DReverse(head); //Call to displaying reversre...
break;
case 8:
Count(head); //Call to counting records...
break;
case 9:
exit(); //Exit...
default :
printf("
You entered wrong choice.
");
}
printf("
Do you want to Exit(Y/N)???
");
flushall();
scanf("%c",&op);
}while(op=='n' op=='N');
}
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