How to create half of the string in uppercase and the other half in lowercase?
Last Updated :
23 Jul, 2025
The first thing that we have to keep in my mind while solving this kind of problem is that the strings are immutable i.e,
If I am taking the following string
var string1 = "geeksforgeeks";
string1[0] = "G";
console.log(string1);
As strings are immutable, so we cannot change the character of the string, so the output of the above code will be the following.
Output:
geeksforgeeks
Approach:
There are several ways to solve this problem. Some of them are as follows.
- Splitting the string into 2 different parts and changing the first part to the UPPERCASE and concatenating the new strings to get the output.
- Create an empty string and add each character of the string to it using FOR loop.
- Using the slicing property of strings to get the output.
Method 1: This method is implemented using 2 new variables.
- Add the string into the variable.
- Store the length of the string into a variable using string.length function.
- Create two empty strings which are used in the future to store the newly created strings.
- Use of for loops to traverse in the string.
- Convert the first string to the upper case using toUpperCase().
- Concatenate both of the strings to get the output.
C++
#include <iostream>
using namespace std;
int main() {
string str = "geeksforgeeks",ans;
int len = str.length();
for(int i = 0;i<len;i++){
if(i<=len/2){
char a = toupper(str[i]);
ans.push_back(a);
}else
ans.push_back(str[i]);
}
cout<<ans;
return 0;
}
// This code is co ntributed by rohitsingh07052
public class GFG {
public static void main(String[] args) {
// Input string
String str = "geeksforgeeks";
// StringBuilder to store the result
StringBuilder ans = new StringBuilder();
// Get the length of the input string
int len = str.length();
// Loop through each character in the input string
for (int i = 0; i < len; i++) {
// Check if the current character is in the first half of the string
if (i <= len / 2) {
// Convert the character to uppercase and append it to the result
char a = Character.toUpperCase(str.charAt(i));
ans.append(a);
} else {
// If the character is in the second half, just append it as is
ans.append(str.charAt(i));
}
}
// Print the final result
System.out.println(ans);
}
}
import math
string1 = 'geeksforgeeks'
string1_len = len(string1)
part_a = ''
part_b = ''
for i in range(int(math.ceil(string1_len // 2 + 1))):
part_a += string1[i]
for i in range(int(math.ceil(string1_len // 2)) + 1,
string1_len):
part_b += string1[i]
new_part_a = part_a.upper()
changed_string = new_part_a + part_b
print(changed_string)
# This code is contributed by ukasp
using System;
public class GFG
{
public static void Main(string[] args)
{
// Input string
string str = "geeksforgeeks";
// String builder to store the result
System.Text.StringBuilder ans = new System.Text.StringBuilder();
// Get the length of the input string
int len = str.Length;
// Loop through each character in the input string
for (int i = 0; i < len; i++)
{
// Check if the current character is in the first half of the string
if (i <= len / 2)
{
// Convert the character to uppercase and append it to the result
char a = char.ToUpper(str[i]);
ans.Append(a);
}
else
{
// If the character is in the second half, just append it as is
ans.Append(str[i]);
}
}
// Print the final result
Console.WriteLine(ans);
}
}
<script>
var string1 = 'geeksforgeeks';
var string1_len = string1.length;
var part_a = '';
var part_b = '';
for(var i=0 ; i<Math.ceil(string1_len/2) ; i++)
{
part_a+=string1[i];
}
for(var i=Math.ceil(string1_len/2) ; i<string1_len ; i++)
{
part_b+=string1[i];
}
var new_part_a = part_a.toUpperCase();
var changed_string = new_part_a + part_b;
console.log(changed_string);
</script>
Time Complexity: O(N)
Auxiliary Space: O(1)
Method 2: This method is implemented using a single new variable.
- Add the string into the variable.
- Store the length of the string into a variable using string.length function.
- Create an empty string that is used in the future to store the newly created string.
- Use of for loops to traverse the string.
- Log the final string to get the output.
C++
#include <iostream>
using namespace std;
string convertFun(string& s1, int n)
{
string ans = "";
// Running loop on first half and making it
// upper case
for (int i = 0; i < n / 2; i++) {
ans += toupper(s1[i]);
}
// Running loop on secone half
for (int i = n / 2; i < n; i++) {
ans += s1[i];
}
return ans;
}
// Driver code
int main()
{
string s1 = "geeksforgeeks";
// Finding length of string
int n = s1.size();
cout << convertFun(s1, n);
return 0;
}
// This code is added by Arpit Jain
public class StringConversion {
// Function to convert the first half of the string to
// uppercase
static String convertFun(String s1, int n)
{
StringBuilder ans = new StringBuilder();
// Running loop on the first half and making it
// uppercase
for (int i = 0; i < n / 2; i++) {
ans.append(Character.toUpperCase(s1.charAt(i)));
}
// Running loop on the second half
for (int i = n / 2; i < n; i++) {
ans.append(s1.charAt(i));
}
return ans.toString();
}
// Driver code
public static void main(String[] args)
{
String s1 = "geeksforgeeks";
// Finding the length of the string
int n = s1.length();
System.out.println(convertFun(s1, n));
}
}
import math
string1 = 'gfg';
string1_len = len(string1)
changed_string = ''
for i in range(math.ceil(string1_len/2)):
changed_string += string1[i].upper();
for i in range(math.ceil(string1_len/2), string1_len):
changed_string += string1[i]
print(changed_string)
# This code is contributed by avanitrachhadiya2155
using System;
class Program
{
// Function to convert the first half of the string to uppercase
static string ConvertFun(string s1, int n)
{
string ans = "";
// Running loop on the first half and making it upper case
for (int i = 0; i < n / 2; i++)
{
ans += char.ToUpper(s1[i]);
}
// Running loop on the second half
for (int i = n / 2; i < n; i++)
{
ans += s1[i];
}
return ans;
}
// Driver code
static void Main()
{
string s1 = "geeksforgeeks";
// Finding the length of the string
int n = s1.Length;
Console.WriteLine(ConvertFun(s1, n));
// This code is added by Arpit Jain
}
}
// This code is contributed by shivamgupta310570
<script>
var string1 = 'gfg';
var string1_len = string1.length;
var changed_string = '';
for(var i=0 ; i<Math.ceil(string1_len/2) ; i++)
{
changed_string+=string1[i].toUpperCase();
}
for(var i=Math.ceil(string1_len/2) ; i<string1_len ; i++)
{
changed_string+=string1[i];
}
console.log(changed_string);
</script>
Time Complexity: O(N)
Auxiliary Space: O(1)
Method 3: This method is implemented using the JavaScript Slice property.
- Add the string into the variable.
- Store the length of the string into a variable using string.length function.
- Store the ceil value of half of the length of the string to the new variable.
- Create 2 empty strings which are used in the future to store the newly created strings.
- Add string to the variables using string slicing property.
- Convert the first string to the upper case using toUpperCase().
- Concatenate both of the strings to get the output.
C++
#include <cmath>
#include <iostream>
int main()
{
// Given string
std::string string1 = "geeks for geeks";
// Calculate the length of the string
int string1Len = string1.length();
// Calculate the index to split the string into two
// halves
int halfString
= static_cast<int>(std::ceil(string1Len / 2.0));
// Declare variables to store the two parts of the
// string
std::string partA;
std::string partB;
// Extract the first half of the string
partA = string1.substr(0, halfString);
// Convert the first half to uppercase
for (char& ch : partA) {
ch = std::toupper(ch);
}
// Extract the second half of the string
partB = string1.substr(halfString, string1Len);
// Concatenate the modified first half and the second
// half
std::string changedString = partA + partB;
// Print the modified string
std::cout << changedString << std::endl;
return 0;
}
public class Main {
public static void main(String[] args) {
// Given string
String string1 = "geeks for geeks";
// Calculate the length of the string
int string1Len = string1.length();
// Calculate the index to split the string into two halves
int halfString = (int) Math.ceil(string1Len / 2.0);
// Declare variables to store the two parts of the string
String partA;
String partB;
// Extract the first half of the string
partA = string1.substring(0, halfString);
// Convert the first half to uppercase
String newPartA = partA.toUpperCase();
// Extract the second half of the string
partB = string1.substring(halfString, string1Len);
// Concatenate the modified first half and the second half
String changedString = newPartA + partB;
// Print the modified string
System.out.println(changedString);
}
}
import math
string1 = 'geeksforgeeks'
string1_len = len(string1)
half_string = math.ceil(string1_len/2)
part_a = ''
part_b = ''
part_a = string1[:half_string]
new_part_a = part_a.upper()
part_b = string1[half_string:string1_len]
changed_string = new_part_a+part_b
print(changed_string)
# This code is contributed by rag2127
using System;
class Program
{
static void Main()
{
// Given string
string string1 = "geeks for geeks";
// Calculate the length of the string
int string1Len = string1.Length;
// Calculate the index to split the string into two halves
int halfString = (int)Math.Ceiling(string1Len / 2.0);
// Extract the first half of the string
string partA = string1.Substring(0, halfString);
// Convert the first half to uppercase
partA = partA.ToUpper();
// Extract the second half of the string
string partB = string1.Substring(halfString, string1Len - halfString);
// Concatenate the modified first half and the second half
string changedString = partA + partB;
// Print the modified string
Console.WriteLine(changedString);
}
}
<script>
var string1 = 'geeks for geeks';
var string1_len = string1.length;
var half_string = Math.ceil(string1_len/2);
var part_a;
var part_b;
part_a = string1.slice(0,half_string);
var new_part_a = part_a.toUpperCase();
part_b = string1.slice(half_string,string1_len);
var changed_string = new_part_a+part_b;
console.log(changed_string);
</script>
Time Complexity: O(N)
Auxiliary Space: O(N)
In these ways, you can solve these kinds of problems.
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