Character Functions in Java

☞These functions deal only with character manipulations.

☞Some of them are :

1)	isLetter()
2)	isDigit()
3)	isLetterOrDigit()
4)	isWhitespace()
5)	isUpperCase()
6)	isLowerCase()
7)	toUpperCase()
8)	toLowerCase()

☞These functions are of the Character class.

☞To use these Character class functions, you must write Character.<function_name()>

Character.isLetter()

☞To check whether the given character is letter or not.

☞It returns boolean value.

Example

class IsLetter{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isLetter(ch1));  
        System.out.println(Character.isLetter(ch2));  
        System.out.println(Character.isLetter(ch3));  
        System.out.println(Character.isLetter(ch4));  
        System.out.println(Character.isLetter(ch5));  
        
    }
}

Output

true
false
true
false
false

Character.isDigit()

☞To check whether the given character is digit or not.

☞It returns boolean value.

Example

class IsDigit{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isDigit(ch1));   
        System.out.println(Character.isDigit(ch2));   
        System.out.println(Character.isDigit(ch3));   
        System.out.println(Character.isDigit(ch4));   
        System.out.println(Character.isDigit(ch5));   
  
        
    }
}

Output

false
true
false
false
false

Character.isLetterOrDigit()

☞To check whether the given character is either letter or digit.

☞It returns boolean value.

Example

class IsLetterOrDigit{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isLetterOrDigit(ch1));  
        System.out.println(Character.isLetterOrDigit(ch2));  
        System.out.println(Character.isLetterOrDigit(ch3));  
        System.out.println(Character.isLetterOrDigit(ch4)); 
        System.out.println(Character.isLetterOrDigit(ch5)); 
   
    }
}

Output

true
true
true
false
false

Character.isWhitespace()

☞To check whether the given character is space or not.

☞It returns boolean value.

Example

class IsWhitespace{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isWhitespace(ch1));  
        System.out.println(Character.isWhitespace(ch2));  
        System.out.println(Character.isWhitespace(ch3));  
        System.out.println(Character.isWhitespace(ch4));  
        System.out.println(Character.isWhitespace(ch5));  

    }
}

Output

false
false
false
false
true

Character.isUpperCase()

☞To check whether the given character is capital letter or not.

☞It returns boolean value.

Example

class IsUpperCase{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isUpperCase(ch1));  
        System.out.println(Character.isUpperCase(ch2));  
        System.out.println(Character.isUpperCase(ch3));  
        System.out.println(Character.isUpperCase(ch4));  
        System.out.println(Character.isUpperCase(ch5));  
  
    }
}

Output

true
false
false
false
false

Character.isLowerCase()

☞To check whether the given character is small letter or not.

☞It returns boolean value.

Example

class IsLowerCase{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.isLowerCase(ch1));  
        System.out.println(Character.isLowerCase(ch2));  
        System.out.println(Character.isLowerCase(ch3));  
        System.out.println(Character.isLowerCase(ch4));  
        System.out.println(Character.isLowerCase(ch5));  

    }
}

Output

false
false
true
false
false

Character.toUpperCase()

☞To convert the small letter into capital letter.

Example 

class ToUpperCase{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.toUpperCase(ch1));  
        System.out.println(Character.toUpperCase(ch2));  
        System.out.println(Character.toUpperCase(ch3));  
        System.out.println(Character.toUpperCase(ch4));  
        System.out.println(Character.toUpperCase(ch5));  
        
    }
}

Output

A
2
A
#
       //space is printed

Character.toLowerCase()

☞To convert the capital letter into small letter.

Example 

class T0LowerCase{
    public static void main(String args[]){
        
        char ch1='A';
        char ch2='2';
        char ch3='a';
        char ch4='#';
        char ch5=' ';
        
        System.out.println(Character.toLowerCase(ch1));  
        System.out.println(Character.toLowerCase(ch2));  
        System.out.println(Character.toLowerCase(ch3));  
        System.out.println(Character.toLowerCase(ch4));  
        System.out.println(Character.toLowerCase(ch5));  
  

    }
}

Output

a
2
a
#
      //space is printed