﻿ C Program: Find maximum value from a doubly linked list - w3resource

# C Exercises: Find maximum value from a doubly linked list

## C Doubly Linked List : Exercise-11 with Solution

Write a program in C to find the maximum value in a doubly linked list.

Visual Presentation:

Sample Solution:

C Code:

``````#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

struct node {
int num;
struct node *preptr;
struct node *nextptr;
} *stnode, *ennode;

// Function prototypes
void DlListcreation(int n);
int getMaxNode(struct node *stnode);
void displayDlList();

int main() {
int n;
stnode = NULL;
ennode = NULL;

// User input for the number of nodes
printf("\n\n Doubly Linked List : Find maximum value from a doubly linked list :\n");
printf("--------------------------------------------------------------------------\n");
printf(" Input the number of nodes : ");
scanf("%d", &n);

// Creating the doubly linked list
DlListcreation(n);
displayDlList();

// Finding and displaying the maximum value in the linked list
printf("\n The Maximum Value in the Linked List : %d\n\n", getMaxNode(stnode));
return 0;
}

// Function to create a doubly linked list
void DlListcreation(int n) {
int i, num;
struct node *fnNode;

if (n >= 1) {
stnode = (struct node *)malloc(sizeof(struct node));

if (stnode != NULL) {
// Input data for the first node
printf(" Input data for node 1 : ");
scanf("%d", &num);

stnode->num = num;
stnode->preptr = NULL;
stnode->nextptr = NULL;
ennode = stnode;

// Loop to create subsequent nodes and link them
for (i = 2; i <= n; i++) {
fnNode = (struct node *)malloc(sizeof(struct node));
if (fnNode != NULL) {
printf(" Input data for node %d : ", i);
scanf("%d", &num);
fnNode->num = num;
fnNode->preptr = ennode;    // Linking new node with the previous node
fnNode->nextptr = NULL;

ennode->nextptr = fnNode;   // Linking previous node with the new node
ennode = fnNode;            // Assigning new node as last node
} else {
printf(" Memory can not be allocated.");
break;
}
}
} else {
printf(" Memory can not be allocated.");
}
}
}

// Function to find the maximum value in the linked list
int getMaxNode(struct node *stnode) {
if (stnode == NULL) {
printf(" User message : Invalid Input !!!!\n");
return INT_MIN; // Returning the minimum integer value when list is empty
}

int max = stnode->num;
while (stnode != NULL) {
if (stnode->num > max) {
max = stnode->num;
}
stnode = stnode->nextptr;
}
return max;
}

// Function to display the doubly linked list
void displayDlList() {
struct node *tmp;
int n = 1;
if (stnode == NULL) {
printf(" No data found in the List yet.");
} else {
tmp = stnode;
printf("\n\n Data entered in the list are :\n");

// Loop to display nodes and their data
while (tmp != NULL) {
printf(" node %d : %d\n", n, tmp->num);
n++;
tmp = tmp->nextptr; // Moving the current pointer to the next node
}
}
}
```
```

Sample Output:

``` Doubly Linked List : Find maximum  value from a doubly linked list :
--------------------------------------------------------------------------
Input the number of nodes : 3
Input data for node 1 : 5
Input data for node 2 : 9
Input data for node 3 : 1

Data entered in the list are :
node 1 : 5
node 2 : 9
node 3 : 1

The Maximum Value in the Linked List : 9
```

Flowchart:

DlListcreation() :

getMaxNode() :

displayDlList() :

C Programming Code Editor:

What is the difficulty level of this exercise?

Test your Programming skills with w3resource's quiz.

﻿