How to Change a Char to Lowercase in Java
Convert characters of a string to opposite case
Given a string, convert the characters of the string into opposite case,i.e. if a character is lower case then convert it into upper case and vice-versa.
Examples:
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Input : geeksForgEeks Output : GEEKSfORGeEKS Input : hello every one Output : HELLO EVERY ONE
ASCII values of alphabets: A – Z = 65 to 90, a – z = 97 to 122
Steps:
- Take one string of any length and calculate its length.
- Scan string character by character and keep checking the index.
- If a character in an index is in lower case, then subtract 32 to convert it in upper case, else add 32 to convert it in lower case
- Print the final string.
C++
#include <iostream>
using namespace std;
void convertOpposite(string& str)
{
int ln = str.length();
for ( int i = 0; i < ln; i++) {
if (str[i] >= 'a' && str[i] <= 'z' )
str[i] = str[i] - 32;
else if (str[i] >= 'A' && str[i] <= 'Z' )
str[i] = str[i] + 32;
}
}
int main()
{
string str = "GeEkSfOrGeEkS" ;
convertOpposite(str);
cout << str;
return 0;
}
Java
class Test {
static void convertOpposite(StringBuffer str)
{
int ln = str.length();
for ( int i = 0 ; i < ln; i++) {
Character c = str.charAt(i);
if (Character.isLowerCase(c))
str.replace(i, i + 1 ,
Character.toUpperCase(c) + "" );
else
str.replace(i, i + 1 ,
Character.toLowerCase(c) + "" );
}
}
public static void main(String[] args)
{
StringBuffer str
= new StringBuffer( "GeEkSfOrGeEkS" );
convertOpposite(str);
System.out.println(str);
}
}
Python3
def convertOpposite( str ):
ln = len ( str )
for i in range (ln):
if str [i] > = 'a' and str [i] < = 'z' :
str [i] = chr ( ord ( str [i]) - 32 )
elif str [i] > = 'A' and str [i] < = 'Z' :
str [i] = chr ( ord ( str [i]) + 32 )
if __name__ = = "__main__" :
str = "GeEkSfOrGeEkS"
str = list ( str )
convertOpposite( str )
str = ''.join( str )
print ( str )
C#
using System;
using System.Text;
class GFG{
static void convertOpposite(StringBuilder str)
{
int ln = str.Length;
for ( int i=0; i<ln; i++)
{
if (str[i]>= 'a' && str[i]<= 'z' )
str[i] = ( char )(str[i] - 32);
else if (str[i]>= 'A' && str[i]<= 'Z' )
str[i] = ( char )(str[i] + 32);
}
}
public static void Main()
{
StringBuilder str = new StringBuilder( "GeEkSfOrGeEkS" );
convertOpposite(str);
Console.WriteLine(str);
}
}
Javascript
<script>
function convertOpposite(str)
{
var ln = str.length;
for ( var i = 0; i < ln; i++)
{
if (str[i] >= 'a' && str[i] <= 'z' )
document.write(
String.fromCharCode(str.charCodeAt(i) - 32)
);
else if (str[i] >= 'A' && str[i] <= 'Z' )
document.write(
String.fromCharCode(str.charCodeAt(i) + 32)
);
}
}
var str = "GeEkSfOrGeEkS" ;
convertOpposite(str);
</script>
Time Complexity: O(n)
Note: This program can alternatively be done using C++ inbuilt functions – Character.toLowerCase(char) and Character.toUpperCase(char).
Approach 2: The problem can be solved using letter case toggling. Follow the below steps to solve the problem:
- Traverse the given string S.
- For each character Si , do Si = S i ^ (1 << 5).
- S i ^ (1 << 5) toggles the 5th bit which means 97 will become 65 and 65 will become 97:
- 65 ^ 32 = 97
- 97 ^ 32 = 65
- Print the string after all operations
Below is the implementation of the above approach:
C++
#include<bits/stdc++.h>
using namespace std;
void toggleChars(string &S)
{
for ( auto &it : S){
if ( isalpha (it)){
it ^= (1 << 5);
}
}
}
int main()
{
string S = "GeKf@rGeek$" ;
toggleChars(S);
cout << "String after toggle " << endl;
cout << S << endl;
return 0;
}
Java
import java.util.*;
class GFG{
static char []S = "GeKf@rGeek$" .toCharArray();
static void toggleChars()
{
for ( int i = 0 ; i < S.length; i++)
{
if (Character.isAlphabetic(S[i]))
{
S[i] ^= ( 1 << 5 );
}
}
}
public static void main(String[] args)
{
toggleChars();
System.out.print( "String after toggle " + "\n" );
System.out.print(String.valueOf(S));
}
}
C#
using System;
class GFG{
static char []S = "GeKf@rGeek$" .ToCharArray();
static void toggleChars()
{
for ( int i = 0; i < S.Length; i++)
{
if ( char .IsLetter(S[i]))
{
S[i] = ( char )(( int )(S[i]) ^ (1 << 5));
}
}
}
public static void Main(String[] args)
{
toggleChars();
Console.Write( "String after toggle " + "\n" );
Console.Write(String.Join( "" , S));
}
}
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How to Change a Char to Lowercase in Java
Source: https://www.geeksforgeeks.org/convert-alternate-characters-string-upper-case/