Comparing Visual FoxPro to Other Programming Languages

ID: Q130456

The information in this article applies to:

Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b

SUMMARY

Most programming languages have similar features. If you are familiar with one programming language, you can easily translate this knowledge to another language. This article compares how BASIC, C/C++, Pascal and Visual FoxPro implement the basic programming constructs in the following areas:

Dealing with case sensitivity.

Declarating variables.

Adding comments.

Storing values to variables (assignment statements).

Structuring IF, CASE, FOR and WHILE statements.

Passing parameters by value and by reference.

MORE INFORMATION

Dealing with Case Sensitivity

Only C/C++ is a case-sensitive programming language.


 - BASIC          not case sensitive
 - C/C++          case sensitive
 - Pascal         not case sensitive
 - Visual FoxPro  not case sensitive

Declaring Variables

When you assign a value to a variable (other than an array) that does not exist, Visual FoxPro implicitly declares it. (Arrays must be declared using the DIMENSION command). Languages that require explicit declaration of variables return an error.


 - BASIC          Variables can be implicitly declared
 - C/C++          Variables must be explicitly declared
 - Pascal         Variables must be explicitly declared
 - Visual FoxPro  Variables are implicitly declared

Adding Comments

Each language has its own format for adding comments to programs. Visual FoxPro has different formats for whole line comments and for comments on partial lines.


 - BASIC          ' comment
 - C/C++          // comment
                  /* comment block */ 
 - Pascal         { comment block }
 - Visual FoxPro  * full-line comment
 - Visual FoxPro  && partial-line comment

Storing Values to Variables (Assignment Statements)

Pascal requires a colon in the assignment statement.


 - BASIC          nVal = 7
 - C/C++          nVal = 7
 - Pascal         nVal := 7
 - Visual FoxPro  nVal = 7
                  STORE 7 TO nVal

NOTE: In Visual FoxPro, you can also assign values to fields in a table by using the REPLACE command.

Structuring IF Statements

Each language offers equivalent IF functionality.


 - BASIC          If nCnt < nMax Then
                     nTot = nTot * nCnt
                     nCnt = nCnt + 1
                  End If

 - C/C++          if(nCnt < nMax) {
                     nTot *= nCnt;
                     nCnt++;
                  }

 - Pascal         if nCnt < nMax then
                     begin
                     nTot:=nTot * nCnt;
                     nCnt:=nCnt   + 1;
                  end

 - Visual FoxPro  IF nCnt < nMax
                     nTot = nTot * nCnt
                     nCnt = nCnt + 1
                  ENDIF

Structuring CASE Statements

Only Pascal does not offer ranges in CASE statements.


 - BASIC          Select Case n
                     Case 0
                        Print 'Zero'
                     Case Is > 0
                        Print 'Pos'
                     Case Else
                        Print 'Neg'
                  End Select

 - C/C++          switch(n) {
                     case 0:
                        printf("Zero\n");
                        break;
                     case 1:
                        printf("One\n");
                        break;
                     default:
                        printf("?\n");}

 - Pascal         case n of
                     0: writeln("Zero");
                     1: writeln("One");
                  end

 - Visual FoxPro  DO CASE
                     CASE n = 0
                        ? 'Zero'
                     CASE n > 0
                        ? 'Pos'
                     OTHERWISE
                        ? 'Neg'
                   ENDCASE

Structuring FOR Loops

Each language offers a FOR statement. C/C++ has the most flexibility for expressions.


 - BASIC          For n = 1 to 10
                     Print n
                  Next n

 - C/C++          for(n=1; n<11; n++)
                     printf("%d\n",n);

 - Pascal         for n := 1 to 10 do
                     writeln(n);

 - Visual FoxPro  FOR n = 1 TO 10
                     ? n
                  ENDFOR | NEXT

Structuring WHILE Loops

Each language offers equivalent WHILE loop functionality.


 - BASIC          While n < 100
                     n = n + n
                  Wend

 - C/C++          while(n < 100)
                     n += n;

 - Pascal         while n < 100 do
                     n := n + n;

 - Visual FoxPro  DO WHILE n < 100
                     n = n + n
                  ENDDO

Passing Parameters by Value

Each language permits passing parameters by value.


 - BASIC          ABC ByVal X
 - C/C++          ABC(X);
 - Pascal         procedure ABC (x:integer);
 - Visual FoxPro  =ABC(X)

Passing Arguments by Reference

You can pass parameters by reference two ways in Visual FoxPro.


 - BASIC            ABC X

 - C/C++            ABC(&VAR);

 - Pascal           procedure ABC
                    var x:integer);

 - Visual FoxPro    =ABC(@X)
                    DO ABC WITH X

NOTE: By default, Visual FoxPro passes variables by value. However, you may use the SET UDFPARMS command to specify whether FoxPro passes parameters by value or by reference.

Syntax: SET UDFPARMS TO <VALUE> or <REFERENCE>

For more information on the SET UDFPARMS command, please see the "SET UDFPARMS" topic in Visual FoxPro Help file.

For more programming language comparisons, please see the "Visual FoxPro and Other Programming Lauguages" topic in the Visual FoxPro Help file.

Additional query words:

Keywords : FxinteropGeneral
Version : 3.00 3.00b
Platform : WINDOWS
Issue type :