DOCUMENT:Q130456 26-AUG-1999 [foxpro] TITLE :Comparing Visual FoxPro to Other Programming Languages PRODUCT :Microsoft FoxPro PROD/VER:3.00 3.00b OPER/SYS: KEYWORDS: ====================================================================== ------------------------------------------------------------------------------- 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 or 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 : Technology : kbVFPsearch kbAudDeveloper kbVFP300 kbVFP300b Version : 3.00 3.00b ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 1999.