There are four variants of indexOf[] method. This article depicts about all of them, as follows:
1.int indexOf[] : This method returns the index within this string of the first occurrence of the specified character or -1, if the character does not occur.
Java
public class Index1 {
public static void main[String args[]]
{
String gfg = new String["Welcome to geeksforgeeks"];
System.out.print["Found g first at position : "];
System.out.println[gfg.indexOf['g']];
}
}
Output
Found g first at position : 112. int indexOf[char ch, int strt ] : This method returns the index within this string of the first occurrence of the specified character, starting the search at the specified index or -1, if
the character does not occur.
Java
public class Index2 {
public static void main[String args[]]
{
String gfg = new String["Welcome to geeksforgeeks"];
System.out.print["Found g after 13th index at position : "];
System.out.println[gfg.indexOf['g', 13]];
}
}
Output
Found g after 13th index at position : 193.int indexOf[String str] : This
method returns the index within this string of the first occurrence of the specified substring. If it does not occur as a substring, -1 is returned.
Java
public class Index3 {
public static void main[String args[]]
{
String Str = new String["Welcome to geeksforgeeks"];
String subst = new String["geeks"];
System.out.print["Found geeks starting at position : "];
System.out.print[Str.indexOf[subst]];
}
}
Output
Found geeks starting at position : 114. int indexOf[String str, int strt] : This method returns the index within this string of the first occurrence of the specified substring, starting at the specified index. If it does not occur, -1 is returned.
Java
public class Index4 {
public static void main[String args[]]
{
String Str = new String["Welcome to geeksforgeeks"];
String subst = new String["geeks"];
System.out.print["Found geeks[after 14th index] starting at position : "];
System.out.print[Str.indexOf[subst, 14]];
}
}
Output
Found geeks[after 14th index] starting at position : 19Some related applications:
- Finding out if a given
character [maybe anything upper or lower case] is a vowel or consonant.
Implementation is given below:
JAVA
class Vowels
{
public static boolean vowel[char c]
{
return "aeiouAEIOU".indexOf[c]>=0;
}
public static void main[String[] args]
{
boolean isVowel = vowel['a'];
if[isVowel]
System.out.println["Vowel"];
else
System.out.println["Consonant"];
}
}
This article is contributed by Astha Tyagi. If you like GeeksforGeeks and would like to contribute, you can also write an article using write.geeksforgeeks.org or mail
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