why searching function does not printing the position the element i searched? - c

Question

//declaing headers
#include<stdio.h>
#include<iostream>
#include<stdlib.h>
#include<conio.h>
//creating nodes which having data and next ptr
struct Node{ //creating node
int data;
struct Node *next;
}node;
struct Node *head;
//function declarations
void start_insertion();
void end_insertion();
void display();
void start_deletion();
void end_deletion();
void searching();
//main function
int main(){
int ch;
do{
printf("\n1: Insertion in begining\n2: Insertion in End\n");
printf("3: Deletion from beigning\n4: Deletion from End\n");
printf("5: search\n 0: Exit\n");
display();
printf("\nEnter the choice : ");
scanf("%1d",&ch);
switch(ch){
case 1: start_insertion();
break;
case 2: end_insertion();
break;
case 3: start_deletion();
break;
case 4: end_deletion();
break;
case 5: searching();
break;
case 0: exit(0);
break;
default:printf("Entered wrong choice\n");
}
//system("cls");
}while(ch!=0);
return 0;
}
//insertion from starting
void start_insertion() {
struct Node *ptr,*temp;
ptr=(struct Node*)malloc(sizeof(struct Node));
if(ptr==NULL){
printf("overflow");
}
else{
int item;
printf("Enter the data: ");
scanf("%d",&item);
if(head==NULL){
ptr->data=item;
ptr->next=NULL;
head=ptr;
}
else {
temp=head;
ptr->data=item;
ptr->next=temp;
head=ptr;
}
}
}
//insertion in end
void end_insertion(){
struct Node *ptr,*temp;
ptr=(struct Node*)malloc(sizeof(struct Node));
if(ptr==NULL){
printf("Memory overflow");
}
else{
int item;
printf("\nEnter the data : ");
scanf("%d",&item);
if(head==NULL){
ptr->data=item;
ptr->next=NULL;
head=ptr;
}
else{
temp=head;
while(temp->next!=NULL){
temp=temp->next;
}
temp->next=ptr;
ptr->data=item;
ptr->next=NULL;
}
}
}
//deletion from start
void start_deletion(){
if(head==NULL){
printf("\n************List is Empty******************\n");
}
else{
struct Node *temp;
temp=head;
head=temp->next;
free(temp);
}
}
//deletion from end
void end_deletion(){
struct Node *temp,*temp1;
temp=head;
if(temp==NULL){
printf("\n**********List is empty************\n");
}
else{
if(head->next==NULL){
head=NULL;
free(head);
}
else{
while(temp->next!=NULL){
temp1=temp;
temp=temp->next;
}
temp1->next=NULL;
free(temp);
}
}
}
//traverse the entire linkedlist display
void display(){
struct Node *temp;
temp=head;
if(temp==NULL){
printf("\nNo Node existed\n");
}
else{
while(temp!=NULL){
printf("-> %d ->",temp->data);
temp=temp->next;
}
}
}
//its not printing the position
//searching function to print the position of the element you searched.
void searching(){
if(head==NULL){
printf("List is Empty cant search");
}
else{
struct Node *temp;
temp=head;
int flag=0,p[flag],item,i=0;
printf("Enter the data you want to search: ");
scanf("%d",&item);
while(temp!=NULL){
if(temp->data==item){
p[flag]=i;
flag++;
}
i+=1;
temp=temp->next;
}
if(flag==0){ //if flag=0 the their is no data in the list
printf("no data element exist");
}
else{
for(int j=0;j<=flag;j++){
printf("*******found********%d",p[j]+1);
}
}
}
}

Answer 1

void searching(){
if(head==NULL){
printf("List is Empty cant search");
}
else{
struct Node *temp;
temp=head;
int flag=0,item,i=0;
int p[100];
printf("Enter the data you want to search: ");
scanf("%d",&item);
while(temp!=NULL){
if(temp->data==item){
p[flag] = i;
flag++;
}
i+=1;
temp=temp->next;
}
if(flag==0){ //if flag=0 the their is no data in the list
printf("no data element exist");
}
else{
for(int j=0;j<flag;j++){
printf("*******found********%d",p[j]+1);
}
}
}
}
i edit your search function like above.
there are 2 problems:
first, you have to init the array with number of element, your code just init the array with flag elements while flag is 0 in this line.
int flag=0,p[flag],item,i=0;
second, because your trace array p start from 0, with flag elements so you only have to go from 0 -> flag-1, so i edit your for loop to print the result:
for(int j=0;j<flag;j++)
but i think you better do other way to search in linked list:
when you go through your linked list, if you meet the data, you can print the result and break the loop.
if you meet the end of the list (NULL pointer) but still no matched data found, so that means list is not includes the data you want.
it's no need to use additional variables flag or p array to trace result.
like this:
void searching() {
if (head == NULL) {
printf("List is Empty cant search");
} else {
struct Node *temp;
temp = head;
int item, i = 0;
printf("Enter the data you want to search: ");
scanf("%d", &item);
while (temp != NULL) {
if (temp->data == item) {
printf(" found %d at %d", item, i);
break;
}
i += 1;
temp = temp->next;
}
if (temp == NULL) printf("no data element exist");
}
}

Answer 2

i used online compiler i tested the code with
-> 65 ->-> 45 ->-> 89 ->-> 12 ->-> 8 ->-> 45 ->
Enter the choice : 5
Enter the data you want to search: 45
*******found********2*******found********6
add it work but just remove the = here
for(int j=0;j<flag;j++){ //j<flag not j<=flag
printf("*******found********%d",p[j]+1);
}