How to work with FUNCTION
To work with FUNCTION
Step 1
Description:
The function is a subprogram called form within an expression that returns a value through the function name.
Declaration:
function ident (parameters) : type;
Example:
function sumofsquares(n: integer): integer;
Edited By: Norasyikin Mahmud
© 2001 ISC
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051101
To work with Boolean operators
Step 1
Description:
Boolean operators are the special operators are use to combine Boolean expressions;
Declaration:
Operator Operation
not negation
and logical and
or logical or
xor logical xor
Example:
if (player1 > player2) or (player1 >= player2) then
Writeln(' The winner is player 1');
if (player1 <>
Writeln(' The winner is player 2');
To work with relational operators
Step 1
Description:
A sequence of identifiers, separated by compatible operators, that evaluates to TRUE or FALSE
Declaration:
Operator Operation
= Equal
Not equal
<>
Greater than
<= Less or equal
>= Greater or equal
Example:
if player1 > player2 then
Writeln(' The winner is player 1');
if player1 <>
Writeln(' The winner is player 2');
if player1 = player2 then
Writeln(' No winner in this game ');
To work with Binary Arithmetic Operators
Step 1
Description:
Arithmetic operators, which take real or integer operands, include +, –, *, /, div, and mod.
Declaration:
Operator Operation
+ Addition
Subtraction
Multiplication
/ Division
div Integer division
mod remainder
Example:
Writeln('Answer is : ',a+b+c);
Writeln('Answer is : ',a*b*c);
Writeln('Answer is : ',a+b-c);
To work with CASE function
Step 1
Description:
The case statement consists of an expression (the selector) and a list of statements, each prefixed with a case.
Declaration:
case expression of
case: statement;
...
case: statement;
end
Example:
case a of
'm': Writeln('You are the boy');
'f': Writeln('You are the girl');
end;
To work REPEAT …. UNTIL statement
Step 1
Description:
The statements between repeat and until are executed in sequence until, at the end of a sequence, the Boolean expression is True.
Declaration:
repeat
statement;
statement;
...
statement
until expression
Example:
Repeat
y:=(x*x*x+7*x-1)/(x*x-(x+5)/3);
Writeln;
Write(x,'',y);
if y>=0 then Write(' Admit ');
Writeln;
x:=x+0.50
Until x >=4.00;
To work with FOR …. TO statements
Step 1
Description:
The FOR statement is a looping construct designed specifically for count-controlled loops.
Declaration:
FOR variable identifier:= Expressionl TO Expression2 DO
Statement 1;
Statement 2;
Example:
for number:=4 to 9 do
begin
sqnumber:=number*number;
Writeln(number,' ',sqnumber)
End
To work with WHILE statement
Step 1
Description:
The while statements like the IF statements, tests a condition.
Declaration:
WHILE Boolean expression DO
Statements 1;
Statements 2;
Example:
While x <=4.00 do
begin
y:=(x*x*x+7*x-1)/(x*x-(x+5)/3);
Writeln;
Write(x,'',y);
if y>=0 then Write(' Admit ');
Writeln;
x:=x+0.50
end;
To work with IF…….THEN……ELSE statement
Step 1
Description:
The ability in make decisions.
Declaration:
IF Boolean expression
THEN
Statements 1
ELSE
Statements 2;
Statements;
Example:
if a > 10 Then
Writeln(' This integer is more then 10')
Else
Writeln(' This integer is small then 10');
To work with IF…..THEN statement
Step 1
Description:
The ability to make decisions.
Declaration:
IF Boolean expression
THEN
Statements 1;
Statements 2;
Example:
if a > 10 Then
Writeln(' This interger is more then 20');
To work with record
Step 1
Description:
The components of a record are called fields. Each field has its own field identifier and type
Example:
type
student=record
StudentNo:longint;
StudentName:string;
Department:string;
end;
To work with array
Step 1
Description:
Array is a structured group of like elements given a common name.
Declaration:
array [index-type] of element-type
Example:
var
mark:array [1..40] of integer;
To work with real type
Step 1
Description:
A real type defines a set of numbers that can be represented with floating-point notation.
Declaration:
Type Range
Real48 2.9 x 10^–39 .. 1.7 x 10^38
Single 1.5 x 10^–45 .. 3.4 x 10^38
Double 5.0 x 10^–324 .. 1.7 x 10^308
Extended 3.6 x 10^–4951 .. 1.1 x 10^4932
Comp –2^63+1 .. 2^63 –1
Currency –922337203685477.5808.. 922337203685477.5807
Example:
var
a:double;
b:single;
To work with string
Step 1
Description:
A string represents a sequence of characters.
Declaration:
Type Maximum length
ShortString 255 characters 2 to 256 bytes
AnsiString ~2^31 characters
WideString ~2^30 characters
Example:
var
a:string;
To work with char
Step 1
Description:
Delphi has three character types: Char, AnsiChar, and WideChar.
Declaration:
Type Contents
Char A single character
AnsiChar A single character
WideChar A single Unicode character
Example:
var
a:char;
To work with Boolean
Step 1
Description:
The four predefined Boolean types are Boolean, ByteBool, WordBool, and LongBool. Boolean is the preferred type.
Declaration:
Boolean ByteBool, WordBool, LongBool
False <> True
Ord(False) = 0 Ord(False) = 0
Ord(True) = 1 Ord(True) <> 0
Succ(False) = True Succ(False) = True
Pred(True) = False Pred(False) = True
Example:
if X <> 0 then ...;
var OK: Boolean
...
if X <> 0 then OK := True;
if OK then ...;
How to work with integer types
To work with integer types
Step 1
Description:
Fundamental integer types include Shortint, Smallint, Longint, Int64, Byte, Word, and Longword.
Declaration:
Type Range
Shortint –128..127
Smallint –32768..32767
Longint –2147483648..2147483647
Int64 –2^63..2^63–1
Byte 0..255
Word 0..65535
Longword 0..4294967295
Example:
var
a:integer;
b:integer;
c:integer;
To add the item in the DBCombolBox
Step 1
To add the item in the DBCombolBox, first, you need to click the Items properties.
Step 2
After that, insert the Item and finally, click the Ok button.
To add the DBComboBo
Step 1
To add the DBComBo, first, you need to move the mouse to the Data Control object toolbar and then click the DBComboxBo object.
Step 2
Now, you have to insert the DBComboBox in the Form1.
Step 3
Next, you need to select the DataSource and then select the Department in the DataField.
To create the gender with checkbox
Step 1
If you would like to create the gender with checkbox, first, double click the CheckBox1 and it will display a Code Explorer Window. Next, you need to insert the programming as followed;
To create the gender with checkbox
Step 1
To create the gender with checkbox, first you need to double click the DBCheckBox1 and then it will display a Code Explorer Window. Next, you need to insert the programming as followed;
checkbox1.Checked:=not dbcheckbox1.Checked;
To create the gender with checkbox
Step 1
To create the gender with checkbook, first, you need to double click the From1 and then it will display a Code Explorer Window. Later you need to insert the programming as followed;
To create the gender with checkbox
Step 1
To create the gender with checkbook, first, move the mouse to the Standard object toolbar and then click the CheckBox object.
Step 2
After that, you need to insert the CheckBox in the Form1.
Step 3
Later, you need to enter the Female in the Caption.
To create the gender with CheckBox
Step 1
If you wish to create the gender with CheckBox, the first thing you need to do is to move the mouse to the Data Controls object toolbar and then click the DBCheckBox object.
Step 2
Next, you have to insert the DBCheckBox in the Form1.
Step 3
Later, select the DataSource and select the Gender in the DataField.
To create the Department with Edit box
Step 1
To create the Department with Edit box, first you need to move the mouse to the Data Controls object toolbar and then click the DBEdit object.
Step 2
Next, you have to insert the DBEdit in the Form1.
Step 3
Then, select the DataSource and select the Department in the DataField.
To create the student name with Edit box
Step 1
To create the student name with Edit box, first, you need to move the mouse to the Data Controls object toolbar and then click the DBEdit object.
Step 2
Next, you need to insert the DBEdit in the Form1.
Step 3
After that, select the DataSource and select the StudentName in the DataField.
To create the student id with Edit box
Step 1
To create the student id with Edit box, first, you need to move the mouse to the Data Controls object toolbar and then click the DBEdit object.
Step 2
Next, you need to insert the DBEdit in the Form1.
Step 3
Later, select the DataSource and then select the StudentID in the DataField.
To create the Search button
Step 1
To create the search button, the first thing you need to do is to add the Button in the Form1 and then rename the Caption to Search.
Step 2
Next, just double click the Button to show the Code Explorer Window and then set the Program as followed;
To create the Delete button
Step 1
To create the Delete button, first, add the Button in the Form1 and then rename the Caption to Delete.
Step 2
Next, just double click the Button to show the Code Explorer Window and you need to set the Program as followed;
=mrno then abort();
Step 3
Now, you need type and insert the code and set the Program as followed;
procedure Table1BeforeDelete(DataSet: TDataSet);
To create the Add Record button
Step 1
To create the Add Record button, first, add the Button in the Form1 and then rename the Caption to Add Record.
Step 2
Double click the Button to show the Code Explorer Window and then set the Program as followed;
Table1.Append;
To create the Last Record button
Step 1
To create the last record button, first, add the Button in the Form1 and then rename the Caption to Last Record.
Step 2
Next, you have to double click the Button to show the Code Explorer Window and you need to set the Program as followed;
Table1.Last;
To create the Next record button
Step 1
To create the Next button, first, add the Button in the Form1 and then rename the Caption to Next.
Step 2
Next, double click the Button to show the Code Explorer Window and then you need to set the Program as followed;
Table1.Next;
To create the Previous button
Step 1
To create the previous button, first you need to add the Button in the Form1 and then rename the Caption to Previous.
Step 2
After that, double click the Button to show the Code Explorer Window and you need to set the Program as followed;
Table1.Prior;
To create the Go To First button in the database
Step 1
To create the Go To First button in the database, first, you need to add the Button in the Form1 and then rename the Caption to First Record.
Step 2
Next, you need to double click the Button to show the Code Explorer Window. And you need to set the Program as followed:
To create the master or detail form
Step 1
To create the master or detail form, first, you need to open the Database menu and then click the Form Wizard command.
Step 2
Next, in the From Option, select the Create a master/detail form and click the Next button.
Step 3
Now, you must select the master table that you want and click the Next button.
Step 4
Then, select the field that you want and later, click the Next button. You just need to follow the step by step wizard to finish it.
Step 5
Select the detail table that you want and click the Next button.
Step 6
Later, select the field that you want and then click Next button. You just need to follow the step by step wizard to finish it.
Step 7
Finally, you have finished and the picture below appears on your screen.
