Comparing Visual FoxPro to Other Programming Languages

• 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
  
  

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
  
  

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
  
  

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.