Linked List – Toggle Case

Given a Singly Linked List. The task is to check if the characters in a node is vowel if yes then toggle the case of the vowel.

Examples:

Input : C-> p-> l-> u-> s-> p-> l-> u-> s
Output : C p l U s p l U s
The nodes with vowels are ‘u’ toggle the case of the Vowels hence the nodes are ‘U’.

Input : J->U->N->K->V->I->R->U->S->NULL
Output : J u N K V i R u S

Simple Approach:

1. Traverse through all the nodes in the list
2. Check if the data in the node is a vowel
3. If the character is a vowel then toggle the case of the vowel

Implementation of the simple approach:

#include <bits/stdc++.h>
 
using namespace std;
 
// A Linked List Node
struct Node {
    char data;
    struct Node* next;
};
 
// Utility function to create a new node
Node* newNode(char data)
{
    Node* temp = new Node;
    temp->data = data;
    temp->next = NULL;
 
    return temp;
}
 
// Utility function to print the list
void printList(Node* node)
{
    while (node != NULL) {
 
        cout << node->data << " ";
 
        node = node->next;
    }
}
 
// Function to check if a character is a vowel
bool isVowel(char c)
{
    c = tolower(c);
    if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u')
        return true;
    return false;
}
 
// function to toggle the case of the vowels in the list
void toggleCase(Node* head)
{
    Node* p = head;
 
    // Traverse through the nodes in the list
    while (p != NULL) {
        char c = p->data;
        // If the character is a vowel
        if (isVowel(c)) {
            // toggle the case of the vowel
            if (isupper(c))
                c = tolower(c);
            else
                c = toupper(c);
        }
        p->data = c;
        p = p->next;
    }
}
 
// Driver function
int main()
{
    Node* head = newNode('C');
    head->next = newNode('p');
    head->next->next = newNode('l');
    head->next->next->next = newNode('u');
    head->next->next->next->next = newNode('s');
    head->next->next->next->next->next = newNode('p');
  	head->next->next->next->next->next->next = newNode('l');
  	head->next->next->next->next->next->next->next = newNode('u');
  	head->next->next->next->next->next->next->next->next = newNode('s');  	
 
    toggleCase(head);
 
    printList(head);
 
    return 0;
}

Output:

C p l U s p l U s 

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