Java Reference
In-Depth Information
￿ int i = (int) 32.94
Converts the number 32.94 to an integer. The result is
always rounded down. The integer i will become equal to 32.
￿ int i = 2/3
The result of integer division is an integer. The result is rounded
down. Therefore, the variable i will become equal to 0.
The variable f will become equal to approximately 2/3. The
reason is that the result of dividing an integer by a double is a double.
double f = 2/3.0
Exists a method.
int a = Math.max(b,c)
Finds the max of two numbers.
int a = Math.min(b,c)
Finds the min of two numbers.
int a = Math.abs(b)
Finds the absolute value of a number.
Finds the square root of a double.
double a = Math.sqrt(d)
2.10 Important Points
1. A file called must include exactly one public class called Foo .
2. Every Java program has a main method where the program starts executing.
3. Debugging is executing a Java program line by line and monitoring the values of the
variables. Use debugging to isolate errors in your code. Before debugging in NetBeans ,
first set a breakpoint . This is where the program will stop executing and where the
debugging will start.
4. The block of every method starts with an opening brace and finishes with a closing
5. The closing brace of a block should appear exactly under the line of the opening brace.
Select the Source - Format menu in NetBeans to auto-format the code.
6. Add a semicolon (a.k.a., ;) after every statement. However, do not add a semicolon
after an if or a switch statement.
7. Give thought to variable names. Do not name variables x and y when less generic
names are more appropriate.
8. Every variable must start with a lowercase letter. Conversely, the name of every class
starts with a capital letter.
9. Every variable has a scope . This is where the variable is defined. The scope of a variable
starts from the point where it is defined and ends with the end of the innermost block.
The start of a block in Java is denoted by an opening brace, while its end is denoted
by a closing brace.
10. The left side of an assignment operator (i.e., =) must be a variable. For example,
x =4.
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