More about Strings

This chapter accompanies the previous one. Read it for even more info on Strings.

9. The indexOf() Methods

Answer:
erc
The second statement works like this: 
The final string could just as easily have been created with a single call: 
str = str.substring(4,7);

The `indexOf()` Methods

There are four varieties of indexOf() in the Java library. Only the following may be included on the AP examination:

indexOf( String str )

Returns the index of the first occurrence of str or -1 if str is not found.

For example, the following puts the value 4 into location.

String example = "The sea is calm to-night." ;
int location = example.indexOf( "sea" );

The following puts the value -1 into location.

String example = "The sea is calm to-night." ;
int location = example.indexOf( "rats" );

Question 9:
What does the following put into location?
String example = "The sea is calm to-night." ;
int location = example.indexOf( "a" );