String Handling

Contents :

What is Strings??

String Functions:

What is Strings??

A set of Characters enclosed within double quotes (i.e. " ") is known as string.

[Note the default initial value of string is ""].

Assigning of a String variable:

Direct assignment:

Syntax: String variable = "____";
Eg- String str1 = "Good evening !!";

Assignment by using new keyword:

Syntax: String variable = new String( );
Eg- String str2 = new String("Good afternoon !!");

String Functions:

int length()

This function tells the number of characters present in a string. [Note: Space is also counted as a char by the computer].

char charAt(int index)

This function tells the character present on the position entered by the user. [Note: The count starts from 0, i.e. the first char is assigned the position of 0 and then it proceeds as normal]

int indexOf(char c)

This function tells the first position of the character entered in the string.

A modification of this can be to add a position after which the computer will start searching for the char.

int lestIndexOf(char c)

This function tells in which position the specific character appears the last time in a String.

String substring(int startindex)

This function creates another string which is derived from the main string. The int entered tell after which position the sub string starts.

A modification of this can be adding a end position. i.e. start position tells from which position the substring starts and ends at which position. [For your information, in the example the length of the string is 13 (As First position is taken as 0)].

String toLowerCase()

This function converts all the letters in a string to lower case irrespective of the case the char is in.

String toUpperCase()

This function converts all the letters in a string to upper case irrespective of the case the char is in.

String replace(char to_replace, char replacement)

This function replaces the specific character with what you want as replacement of it. (Good for writing Secret messages to each other)

String replace( to_replace_setofcharacters, replacement_setofcharacters)

This function replaces the specific set of character (a sub-string) with the other set of characters (another sub-string).

String concat(String str)

This function joins two or more strings into one big string.

But, we can also make use of the '+' operator to join two strings, instead of using this concat.

boolean equals(String str)

This function checks weather the two strings are equal or not [Note: You cant use '==' operator to check if the two strings are equal are not, as it can only be used for primitive data types && also it is case sensitive].