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Sunday, May 18, 2014
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Type of Statements used in JAVA

9:43 AMSunday, May 18, 2014
Statements are roughly equivalent to sentences in natural languages. A statement forms a complete unit of execution. The following types of expressions can be made into a statement by terminating the expression with a semicolon ( ; )
  • Assignment expressions
  • Any use of ++ or - -
  • Method calls
  • Object creation expressions
These kinds of statement are called expression statement. Here are some example of expression statements :

Avalue = 8933.234;                                          // assignment statement
Avalue++ ;                                                        // increment statement
System . out . println (avalue);                         // method call statement
Integer integerobject = new integer (4);           // object creation statement

In addition to these kinds of expression statements, there are two other kinds of statements. A declaration statement declares a variable. You’ve seen many examples of declaration statement.
Double avalue = 8933.234;            // declaration statement

A control flow statement regulates the order in which statements get executed. For loop and  if statements are both examples of control flow statements.

Block

A block is group of zero or more statements between balanced braces and can be used anywhere a single statement is allowed. The following listing shows two blocks.
If  (character . I suppercase(achar))
{
    Labe l1 . settext (“the character” + achar + “is upper case .”) ;
}
Else
{
    Labe l1. Settext (“the character” + achar + “is lower case .”) ;
    Label2. Settext(“thank you”) ;
}

Character.isLowerCase( )    tests whether a character is in lowercase.
Character.isUpperCase( )        tests whether a character is in uppercase.
Character.toLowerCase( )        converts the case of a character to lowercase
Character.toUpperCase( )        converts the case of a character to uppercase


First Block:
 If (character.isUpperCase(achar))
{            // block1 begins
    Label1.Settext (“ The character “ + achar + “ is upper case.”) ;
}            // end of block 1
Else
 
Another Block:
{            // block2 begins
Label1.Settext(“ The character “ + achar + “ is lower case . “) ;
}            // end of block2

See, the beginning and end of blocks have been marked.
A Block is a group of zero or more statements between balanced braces and can be used anywhere a single statement is allowed.
In this book, we shall be following conventional style where opening brace of the block is not put in a separate line, rather it is placed in continuation with the previous statement (whose part the block is).
For instance, rather than showing
If (a > b) { : }
We shall be writing
If (a > b)   {     :  }
Opening brace of the block in continuation with previous statement
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