There are 4 types of an indexOf method in java. The signature of indexOf methods are given below:
- indexOf(int ch) - Returns the index within this string of the first occurrence of the specified character.
- indexOf(int ch, int fromIndex) - Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.
- indexOf(String str) - Returns the index within this string of the first occurrence of the specified substring.
- indexOf(String str, int fromIndex) - Returns the index within this string of the first occurrence of the specified substring, starting at the specified index.
This program demonstrates the example of all the 4 indexOf() methods.
public class IndexOfExample {
public static void main(String[] args) {
String str = "javaguides";
// method 1
int index = str.indexOf("java");
System.out.println(index);
// Remember index starts with 0 so count from 0
System.out.println("index of guides :: " + str.indexOf("guides"));
System.out.println(" index of des :: " + str.indexOf("des"));
// method 2
System.out.println(str.indexOf('s'));
// method 3
System.out.println(str.indexOf('g', 0));
// method 4
System.out.println(str.indexOf("guides", 3));
}
}
Output:
0 index of guides:: 4 index of des:: 7 9 4 4
Reference
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