Replace every vowels with lexicographically next vowel in a String

Given string str of size N, which contains lowercase English alphabets. The task is to replace each vowel with the next immediate vowel lexicographically, i.e., 

‘a’ will be replaced by ‘e’, 
‘e’ will be replaced by ‘i’, 
‘i’ will be replaced by ‘o’, 
‘o’ will be replaced by ‘u’, 
‘u’ will be replaced by ‘a’.

Examples:  

Input: str = “geeksforgeeks” 
Output: giiksfurgiiks 
Explaination: 
e is replace by i 
o is replace by u 
So final string will be “giiksfurgiiks”.

Input: str = “gfg” 
Output: gfg 



Approach: We will create a Hashing of size 5 to store all vowels so that the replacement can be done easily for each vowel. 

  • Create a map and store all vowels.
  • Iterate the string elements from left to right.
  • It the string element is a vowel, then change it to the next vowels.
  • Finally, print the final string.

Here is the implementation of the above approach:

C++14

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// C++ program to convert all the vowels in
// in the string to the next vowel
 
#include <bits/stdc++.h>
using namespace std;
 
// Function to replace every vowel
// with next vowel lexicographically
string print_next_vovel_string(string str)
{
 
    // Storing the vowels in the map with
    // custom numbers showing  their index
    map<char, int> m;
    m['a'] = 0;
    m['e'] = 1;
    m['i'] = 2;
    m['o'] = 3;
    m['u'] = 4;
    char arr[5] = { 'a', 'e', 'i', 'o', 'u' };
 
    int N = str.length();
 
    // Iterate over the string
    for (int i = 0; i < N; i++) {
 
        char c = str[i];
 
        // If the current character is a vowel
        // Find the index in Hash and
        // Replace it with next vowel from Hash
        if (c == 'a' || c == 'e' || c == 'i'
            || c == 'o' || c == 'u') {
 
            int index = m + 1;
            int newindex = index % 5;
            str[i] = arr[newindex];
        }
    }
 
    return str;
}
 
// Driver function
int main()
{
    string str = "geeksforgeeks";
 
    cout << print_next_vovel_string(str);
    return 0;
}

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Java

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// Java program to convert all the vowels in
// in the String to the next vowel
import java.util.*;
 
class GFG{
 
// Function to replace every vowel
// with next vowel lexicographically
static String print_next_vovel_String(char []str)
{
 
    // storing the vowels in the map with
    // custom numbers showing their index
    HashMap<Character,
            Integer> m = new HashMap<Character,
                                     Integer>();
    m.put('a', 0);
    m.put('e', 1);
    m.put('i', 2);
    m.put('o', 3);
    m.put('u', 4);
 
    char arr[] = { 'a', 'e', 'i', 'o', 'u' };
 
    int N = str.length;
 
    // Iterate over the String
    for(int i = 0; i < N; i++)
    {
        char c = str[i];
 
        // If the current character is a vowel
        // Find the index in Hash and
        // Replace it with next vowel from Hash
        if (c == 'a' || c == 'e' ||
            c == 'i' || c == 'o' ||
            c == 'u')
        {
            int index = m.get(c) + 1;
            int newindex = index % 5;
             
            str[i] = arr[newindex];
        }
    }
    return String.valueOf(str);
}
 
// Driver code
public static void main(String[] args)
{
    String str = "geeksforgeeks";
 
    System.out.print(print_next_vovel_String(
        str.toCharArray()));
}
}
 
// This code is contributed by Amit Katiyar

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Python3

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# Python3 program to convert
# all the vowels in the string
# to the next vowel
 
# Function to replace every vowel
# with next vowel lexicographically
def print_next_vovel_string(st):
 
    # Storing the vowels in
    # the map with custom
    # numbers showing  their index
    m = {}
    m['a'] = 0
    m['e'] = 1
    m['i'] = 2
    m['o'] = 3
    m['u'] = 4
    arr = ['a', 'e', 'i', 'o', 'u']
 
    N = len(st)
 
    # Iterate over the string
    for i in range (N):
 
        c = st[i]
 
        # If the current character
        # is a vowel
        # Find the index in Hash
        # and Replace it with next
        # vowel from Hash
        if (c == 'a' or c == 'e' or
            c == 'i'or c == 'o' or
            c == 'u'):           
            index = m[st[i]] + 1
            newindex = index % 5
            st = st.replace(st[i], arr[newindex], 1)
 
    return st
 
# Driver function
if __name__ == "__main__":
    st = "geeksforgeeks"
    print (print_next_vovel_string(st))
    
# This code is contributed by Chitranayal

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C#

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// C# program to convert all the vowels in
// in the String to the next vowel
using System;
using System.Collections.Generic;
 
class GFG{
 
// Function to replace every vowel
// with next vowel lexicographically
static String print_next_vovel_String(char []str)
{
   
    // Storing the vowels in the map with
    // custom numbers showing their index
    Dictionary<char,
               int> m = new Dictionary<char,
                                       int>();
    m.Add('a', 0);
    m.Add('e', 1);
    m.Add('i', 2);
    m.Add('o', 3);
    m.Add('u', 4);
 
    char []arr = { 'a', 'e', 'i', 'o', 'u' };
 
    int N = str.Length;
 
    // Iterate over the String
    for(int i = 0; i < N; i++)
    {
        char c = str[i];
 
        // If the current character is a vowel
        // Find the index in Hash and
        // Replace it with next vowel from Hash
        if (c == 'a' || c == 'e' ||
            c == 'i' || c == 'o' ||
            c == 'u')
        {
            int index = m + 1;
            int newindex = index % 5;
             
            str[i] = arr[newindex];
        }
    }
    return String.Join("", str);
}
 
// Driver code
public static void Main(String[] args)
{
    String str = "geeksforgeeks";
 
    Console.Write(print_next_vovel_String(
        str.ToCharArray()));
}
}
 
// This code is contributed by Amit Katiyar

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Output: 

giiksfurgiiks




 

Time Complexity: O (N) 
Auxiliary Space: O (1)

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