Java Reference
In-Depth Information
String saying = proverb.toString();
The object saying will contain " Many hands make light work ".
The toString() method is used extensively by the compiler together with the append() method to
implement the concatenation of String objects. When you write a statement such as:
String saying = "Many" + " hands" + " make" + " light" + " work";
the compiler will implement this as:
String saying = new StringBuffer().append("Many").append(" hands").
append(" make").append(" light").
append(" work").toString();
The expression to the right of the = sign is executed from left to right, so the segments of the string are
appended to the StringBuffer object that is created until finally the toString() method is
invoked to convert it to a String object. String objects can't be modified, so any alteration or
extension of a String object will involve the use of a StringBuffer object, which can be changed.
Summary
You should now be thoroughly familiar with how to create and use arrays. Most people have little trouble
dealing with one-dimensional arrays, but arrays of arrays are a bit more tricky so try to practice using these.
You have also acquired a good knowledge of what you can do with String and StringBuffer
objects. Most operations with these objects are very straightforward and easy to understand. Being able
to decide which methods you should apply to the solution of specific problems is a skill that will come
with a bit of practice.
The essential points that we have discussed in this chapter are:
You use an array to hold multiple values of the same type, identified through a single
variable name.
You reference an individual element of an array by using an index value of type int . The index
value for an array element is the offset of that element from the first element in the array.
An array element can be used in the same way as a single variable of the same type.
You can obtain the number of elements in an array by using the length member of the
array object.
An array element can also contain an array, so you can define arrays of arrays, or arrays of
arrays of arrays…
A String object stores a fixed character string that cannot be changed. However, you can
assign a given String variable to a different String object.
You can obtain the number of characters stored in a String object by using the length()
method for the object.
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