| << Chapter < Page | Chapter >> Page > |
Note however, that this array object doesn't contain the actual string data. Rather, it simply sets aside memory for storage of two references to String objects. No memory has been set aside to store the characters that make up the individual strings. You must allocate the memory for the actual String objects separately using code similar to the following.
myArrayOfStringReferences[0] = new String("This is the first string.");
myArrayOfStringReferences[1]= new String(
"This is the second string."); Java supports string concatenation using the overloaded + operator as shown in the following code fragment:
"My variable has a value of " + myVar +
" at this point in the program." String objects cannot be modified once they have been created. StringBuffer objects can be modified
The Java compiler considers a series of characters surrounded by quotation marks to be a literal string, as in the following code fragment:
"This is a literal string in Java." A string is commonly considered to be a sequence of characters stored in memory and accessible as a unit. Java implements strings using the String class and the StringBuffer class.
Java allows you to assign one array to another. When you do this, you are simply making another copy of the reference to the same data in memory. Then youhave two references to the same data in memory. This is illustrated in the program named array02.java in Jb0240: Java OOP: Arrays and Strings .
False. When declaring a two-dimensional array, it is not necessary to declare the size of the secondary dimension when the array is declared. Declaration ofthe size of each sub-array can be deferred until later as illustrated in the program named array01.java in Jb0240: Java OOP: Arrays and Strings .
False. Java can be used to produce multi-dimensional arrays that can be viewed as an array of arrays. However, the secondary arrays need not all be ofthe same size. See the program named array01.java in Jb0240: Java OOP: Arrays and Strings .
Array objects can contain any Java data type including primitive values, references to ordinary objects, and references to other array objects.
All array objects have a length property that can be accessed to determine the number of elements in the array as shown below.
for(int cnt = 0; cnt<myArray.length; cnt++)
myArray[cnt]= cnt; False. Array indices always begin with 0.
False. While it is possible to simultaneously declare the name of the variableand cause memory to be allocated to contain the array object, it is not necessary tocombine these two processes. You can execute one statement to declare the variableand another statement to cause the memory for the array object to be allocated as shown below.
int[] myArray;.
..
myArray = new int[25]; False. As with other objects. the declaration of the variable does not allocate memory to contain the array object. Rather it simply allocates memory tocontain a reference to the array object. Memory to contain the array object must be allocated from dynamic memory using statements such as the following.
int[] myArray = new int[15];
int myArray[]= new int[25];int[] myArray = {1,2,3,4,5} int[] myArray;int myArray[]; In declaring the variable, you must provide two important pieces of information:
False. Java has a true array type and a true String type with protective features to prevent your program from writing outside the memorybounds of the array or the String .
True.
This section contains a variety of miscellaneous information.
Financial : Although the Connexions site makes it possible for you to download aPDF file for this module at no charge, and also makes it possible for you to purchase a pre-printed version of the PDF file, youshould be aware that some of the HTML elements in this module may not translate well into PDF.
I also want you to know that, I receive no financial compensation from the Connexions website even if you purchase the PDF version ofthe module.
In the past, unknown individuals have copied my modules from cnx.org, converted them to Kindle books, and placed them for sale onAmazon.com showing me as the author. I neither receive compensation for those sales nor do I know who does receive compensation. If youpurchase such a book, please be aware that it is a copy of a module that is freely available on cnx.org and that it was made andpublished without my prior knowledge.
Affiliation : I am a professor of Computer Information Technology at Austin Community College in Austin, TX.
-end-
Notification Switch
Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|