Page 347 - Computer science 868 Class 12
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10
STRINGS
Learning Objectives
10.1 ASCII – American Standard Code for Information Interchange
10.2 String Functions 10.3 String Buffer Function
10.4 Conversion from String to Primitive Data Types and Vice Versa 10.5 Stringtokenizer Class
We know that the strings are the combination of different characters. All letters, digits, space and punctuators together
make a String. To declare a string, the following syntax is used.
String sent= “India has 28 states and 9 Union Territories.” Anything inside double quotation marks “ ” is termed as a string.
As we can see a string is a combination of individual characters. So, the size of the string will be the number of characters
× 2. This is because each character occupies 2 bytes. The above sentence will occupy 44 × 2 = 88 bytes in memory.
Before starting to work with string, we must first have an idea of characters. Any letter, digit, or special character when
written in within single quotation marks is known as a Character in Java. A character can be declared using the data
type “char”.
For example, char ch= 'a';
In the above example, ‘ch’ is the character variable which holds the character ‘a’ and it takes 2 bytes space in the
memory.
Similarly, a character can also be taken from user as an input. To input a character, the following syntax is used.
For example, char ch=sc.next().charAt(0);
Java has provided many built-in methods to work with characters. The class under which these built-in methods resides
is known as the “Character” class.
Method Description
Character.isLetter(char) This method checks whether the given character in
the argument is a letter or not. If letter, then it will
return true else false.
Character.isDigit(char) This method checks whether the given character
in the argument is a digit or not. If digit, then it will
return true else false.
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