Here's a program which is found in my text boob of C. I don't know what and how it does the work. When I ran it, it had errors which I rectified somehow.
Code:#include <stdio.h>
#include <conio.h>
#include <alloc.h>
#define NewNode (Node *) malloc(sizeof(Node))
typedef struct node {
int item;
struct node *next;
}Node;
Node * Create(Node *);
void Display(Node *);
int Count(Node *);
Node * Insert(Node *);
Node * Delete(Node *);
void Search(Node *);
void main() {
Node *start = NULL;
int ch, cnt;
clrscr();
start = Create(start);
Display(start);
do {
printf("\n Singly Linked List Operations \n");
printf(" 1-> Count\n");
printf(" 2-> Display\n");
printf(" 3-> Insert\n");
printf(" 4-> Delete\n");
printf(" 5-> Search\n");
printf("\n Enter a Choice: ");
scanf("%d", &ch);
switch(ch) {
case 1:
printf("\n No. of Nodes = %d\n", Count(start));
break;
case 2:
Display(start);
break;
case 3:
start = Insert(start);
break;
case 4:
start = Delete(start);
break;
case 5:
Search(start);
break;
default:
printf("\n Invalid Selection\n");
}
}while(ch !=0);
}
Node * Create(Node *s) {
Node *tmp = NULL, *t1 = NULL;
int num;
t1 =s;
do {
printf("\n Enter the element: ");
scanf("%d", &num);
if(num != -99) {
tmp = NewNode;
tmp->item = num;
tmp->next = NULL;
if(s == NULL)
s = t1 = tmp;
else {
t1->next = tmp;
t1 = t1->next;
}
}
else {
printf("\n Linked List Created Successfully\n");
}
}while(num != -99);
return(s);
}
void Display(Node *s) {
if(s == NULL)
printf("\n Empty Linked List\n");
else {
while(s != NULL) {
printf("%d", s->item);
s = s->next;
}
printf("\n ");
}
}
int Count(Node *s) {
int total = 0;
while(s != NULL) {
total++;
s = s->next;
}
return(total);
}
Node * Insert(Node *s) {
Node *t1 = NULL, *tmp = NewNode;
int pos;
printf("\n Enter the position to be inserted \n");
scanf("%d", &pos);
if(pos > 0 && pos <= Count(s) + 1) {
printf("\n Enter the element to inserted\n");
scanf("%d", &tmp->item);
if(pos == 1) {
tmp->next = s;
s = tmp;
}
else {
t1 = s;
while(pos > 2) {
t1 = t1->next;
pos--;
}
tmp->next = t1->next;
t1->next = tmp;
}
}
else {
printf("\n Invalid Position\n");
}
return(s);
}
Node * Delete(Node *s) {
Node *t1 = s, *tmp = NULL;
int pos;
printf("\n Enter the position to be deleted\n");
scanf("%d", &pos);
if(pos > 0 && pos <= Count(s)) {
if(pos == 1) {
s = s->next;
free(t1);
}
else {
while(pos > 2) {
t1 = t1->next;
pos--;
}
tmp = t1->next;
t1->next = tmp->next;
free(tmp);
}
}
else {
printf("\n Invalid Position\n");
}
return(s);
}
void Search(Node *s) {
int ele;
int flag = 0;
printf("\n Enter the element to be searched: ");
scanf("%d", &ele);
if(s !=NULL) {
while(s != NULL) {
if(s->item == ele) {
printf("\n%d is present\n", ele);
flag = 1;
}
s = s->next;
}
if(flag == 0) {
printf("\nElement Not Found\n");
}
else {
printf("\nList is Empty. Key Element Can't be searched.\n");
}
}
}
Here's the first run of the program:
Code:C:\node
Enter the element: -99
Linked List Created Successfully
Empty Linked List
Singly Linked List Operations
1-> Count
2-> Display
3-> Insert
4-> Delete
5-> Search
Enter a Choice: 3
Enter the position to be inserted
1
Enter the element to inserted
100
Singly Linked List Operations
1-> Count
2-> Display
3-> Insert
4-> Delete
5-> Search
Enter a Choice:
So, any explanation? My text book doesn't say anything about it. :(
