Software Engineers Handbook/Language Dictionary/Visual J++
Visual J++ edit
Here is the Java wikipedia entry.
Type edit
Visual J++ is a full, procedural, object-oriented, visual language.
Execution Entry Point edit
public static void main(String args[]) { // some functionality here }
General Syntax edit
The typical statement is completed by a semi-colon. For the assignment of b to a use:
a = b;
Comments edit
// this is an inline comment. Everything after the // is a comment.
Block comments are specified by a starting /* and ending */ They can span multiple lines.
/* * this is a block comment */
Variable Declarations edit
int x = 9; Integer y = new Integer(4);
Method Declaration/Implementation edit
// declaration private return_type class_name::function_name(argument_1_type arg_1_name, argument_2_type arg_2_name, default_argument_type default_arg_name) { // implementation // work with arg_1_name, arg_2_name, and default_arg_name // depending on the argument types the variables are passed by // value, reference, or are constant // don't forget to return something of the return type return 36; }
Scope edit
Scope is defined by curly braces.
{ // this the beginning of a scope // the scope is about to end }
Conditional Statements edit
If and only if A is equal to B assign C to D, otherwise, assign E to F.
if( A == B ) { D = C; // more code can be added here. It is used if and only if A is equal to B } else { F = E; // more code can be added here. It is used if and only if A is not equal to B }
or
if( A == B ) D = C; //more lines of code are not permitted after this statement else F = E;
Alternatively, a switch statement can be used for multiple choice operations. This sample converts a number input to text.
switch( number_value ) { case 37: text = "thirty-seven"; break; // this line prevents the program from writing over this value with the // following code case 23: text = "twenty-three"; break; default: // this is used if none of the previous cases contain the value text = "unknown number"; }
Looping Statements edit
This code counts from 0 to 9, adding up the contents of the array.
int i = 0; for( int index = 0; index < 10; index = index + 1 ) { i = array[index]; }
This code repeats until the number 4 is found. If this runs off of the end of the array, there could be a problem.
int index = 0; while( 4 != array[index] ) { index = index + 1; }
This code increments the counter before the check is made, so that it starts with element 1.
int index = 0; do { index = index + 1; } while( 4 != array[index] );
Output Statements edit
System.out.println( "Hello World!" );
And adding text to visual components.
Containers edit
Containers inherit from the Collection class. See the java.util package for specific containers including Vector.
Algorithms edit
What algorithms does it have? Does sort work in J++?
Garbage collection edit
Garbage collection is automatic.
Physical Structure edit
Code is generally kept in files with a .java extension. It is compiled into Java byte code into files with .class extensions.
Tips edit
- The language is very similar to Java.
- Visual form layout and component access is similar to other Microsoft Visual development languages.
- Classes in the Java packages are capitalized, methods are not.
- Everything is a pointer. Use a clone method to avoid operating on the original element of a Collection.
- Arrays start with index 0.
- Don't confuse these two:
= // assignment == // comparison, is equal to
Often using the one you don't want will compile, and will produce results you did not expect.
Web References edit
- Java wikibooks page
- Microsoft support is available at the [Microsoft Developers Network] pages.
Books and Articles edit
paper references here