Windows Scripting. Lesson 5. Magic Square

A magic square is one where the total of rows, columns and diagonals is the same.

Take a 3x3 magic square.

The Rules are pretty simple. The rule is called top-left rule.

1. Start with 1. Put it in the centre of the 1st row. So 1 is in (1,2) Row 1, Col 2.

2. Goto top left. In this case top is row 0, so top comes to the 3rd row. Left is row 1. So the next number is (3,1).

3. Continue with top left. Top of 3 is 2, left of 1 is 3rd column. So we are in (2,3).

4. Now the top left from 2,3 is 1,2. This place is occupied, you have a 1 there. So you need to go back to original location (2,3). Then come a place down but same column. So from 2,3 we come to 3,3. Put a 4 here. Continue this way.

5. In this case the totals of rows, col and diagonal is 15. Why 15?

6. We use the natural numbers 1 to 9. Sum of 1 to 9 is n(n+1)/2. In this example we have 9x10/2=45. We have 3 rows. So we get 45/3 or 15.

sub Print(str)     wscript.echo str end sub ' Main Program starts from here dim x(3,3) dim y for a=1 to 3     for b=1 to 3         x(a,b)=0     next next x(1,2)=1 a=1 b=2 for y=2 to 9     olda=a     oldb=b     a=a-1     b=b-1     if a=0 then         a=3     end if     if b=0 then         b=3     end if     if x(a,b)>0 then         a=olda         b=oldb         a=a+1     end if     x(a,b)=y next for a=1 to 3     for b=1 to 3         str=str & chr(9) & x(a,b)     next     wscript.echo str     str=" " next

- print procedure makes the printing easy.

- dim, defines an array. In this case it is an array 3 rows x 3 cols. Each value in the array is defined as 0. 1 is put then in the first row and second column.

- for loop rotates eight times for the eight numbers. a and b are the locations needed. We try top left, and if it is occupied (>0), then we go back to the original location and come one col down.

- the for loop then prints the 3 coloumns. Each row is formatted is by adding a tab (chr(9). When you compile and run this program, (magic3.vbs)

C:\scripts>magic3 //nologo         6       1       8         7       5       3         2       9       4 C:\scripts>

 

Can we make a generic version of this program.  Where we can print for any odd number. Since vbscript does not allow to define an array with a variable, I have defined a large array (20,20) and allow to print a magic square. The beauty is you can pass the number as a parameter. If the parameter is even, then we add 1 and make it a odd number. The program is very similar to the previous program.

sub Print(str)     wscript.echo str end sub sz=int(wscript.arguments(0)) if sz mod 2 = 0 then     print "Argument Should be Odd"     print "Changing to odd"     sz=sz+1 end if 'sz=3 dim x(20,20) dim y for a=1 to sz     for b=1 to sz         x(a,b)=0     next next x(1,(sz+1)/2)=1 a=1 b=(sz+1)/2 for y=2 to (sz * sz)     olda=a     oldb=b     a=a-1     b=b-1     if a=0 then         a=sz     end if     if b=0 then         b=sz     end if     if x(a,b)>0 then         a=olda         b=oldb         a=a+1     end if     x(a,b)=y next for a=1 to sz     for b=1 to sz         str=str & chr(9) & x(a,b)     next     wscript.echo str     str=" " next

Sample output.

C:\scripts>magicgen 5 //nologo         15      8       1       24      17         16      14      7       5       23         22      20      13      6       4         3       21      19      12      10         9       2       25      18      11 C:\scripts>magicgen 7 //nologo         28      19      10      1       48      39      30         29      27      18      9       7       47      38         37      35      26      17      8       6       46         45      36      34      25      16      14      5         4       44      42      33      24      15      13         12      3       43      41      32      23      21         20      11      2       49      40      31      22

An exercise for you. Can you use the n(n+1)/2 formula as mentioned earlier and print one line at the end of the program.

Sum of Rows/Col is _______

Like this

C:\scripts>magicgen 5 //nologo         15      8       1       24      17         16      14      7       5       23         22      20      13      6       4         3       21      19      12      10         9       2       25      18      11 Sum of rows/col is      65

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 4–FileSystemObject Contd..

Continuing on FileSystemObject, Let us look at and example to extract the properties of a file. There are some new things introduced in this example

1. SUB. This is for a procedure. you can pass parameteres just like functions but just that you cannot return any values. I have put a simple procedure called Print, that takes a string as a parameter.

2. Parameteres.  You can pass parameteres to a vbscript. Wscript.argument, is where you can see the list.

Sub Print(x)     wscript.echo x end sub set fso=CreateObject("Scripting.FileSystemObject") set f=fso.GetFile(wscript.arguments(0)) print "Path               " & f.path print "Date Created       " & f.datecreated print "Date Last Accessed " & f.datelastaccessed print "Date last modified " & f.datelastmodified print "Drive              " & f.drivedir print "Parent Folder      " & f.parentfolder print "Size (Bytes)       " & f.size print "Type of File       " & f.type

A few examples

C:\scripts>folder.vbs c:\53-Photos\ar-1.jpg Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. Path                       C:\53-Photos\ar-1.jpg Date Created          09/03/2014 19:50:08 Date Last Accessed  09/03/2014 19:50:08 Date last modified  09/03/2014 19:50:08 Drive                      c: Parent Folder          C:\53-Photos Size (Bytes)             66089 Type of File            JPEG Image C:\scripts>folder folder.vbs Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. Path               C:\scripts\folder.vbs Date Created       18/04/2014 00:01:02 Date Last Accessed 18/04/2014 00:01:02 Date last modified 18/04/2014 01:06:49 Drive              C: Parent Folder      C:\scripts Size (Bytes)       491 Type of File       VBScript Script File C:\scripts>

You can try an example to show the file size in MB or GB depending on the size of the file. Or may be list an output like the DIR command.

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 3–Objects

After the basics of variables, Selection and Iteration statements, let us do something useful in real life. We start with the first object FileSystemObject. This gives us access to the filesystem. An essential part of scripting. We may need to create files, modify content, look for their existence. The idea is to make you familiar with using objects as well.

Let us take an example

Set fs = CreateObject("Scripting.FileSystemObject") Set dc = fs.Drives For Each d in dc     wscript.echo d.driveletter Next

Save this script as fsdrives.vbs

Run it

C:\scripts>cscript fsdrives.vbs //nologo C D F C:\scripts>

I have three drives on my laptop. Your machine may have more or less. Let us understand the code.

Line 1 is creating an object of FileSystemObject type. Without this you cannot use what is in this object. An object is contains methods (functions) and variables. The variables may be simple variables or may be collections. Collections are more like an array, you can use a for loop to go through each of the items, and then access the properties of each.

fs is an instance of the FileSystemObject

fs.drives is referencing a property of the FileSystemObject

fs.drives returns a collection of drives.

To loop through it we need a for loop. dc is the drive collections we have used. You have a collections of drives. For each drive there are many properties. We are referencing one of the property called driveletter.

Let us make the above program more richer. We not only need the drive, but also want to know the capacity and free space.

' Main Code Starts here Set fs = CreateObject("Scripting.FileSystemObject") Set dc = fs.Drives s=chr(10) & "Number of Drives " & dc.count wscript.echo s s=string(65,"-") wscript.echo s For Each d in dc     s=d.driveletter & chr(9) & d.path & chr(9) & d.isready     if d.isready then         s=s & chr(9) & d.volumename         s=s & chr(9) & d.filesystem         ts=int(int(int(d.totalsize/1024)/1024)/1024) & " GB"         s=s & chr(9) & ts           ts=int(int(int(d.freespace/1024)/1024)/1024) & " GB"         s=s & chr(9) & ts           ts=int(int(int(d.availablespace/1024)/1024)/1024) & " GB"         s=s & chr(9) & ts            end if     wscript.echo s Next ' We have explored, volumename, filesystem, totalsize, freespace ' availablespace, driveletter, path and isready properties from ' the drives collection. These values are for each drive. ' chr(9) is for tab and chr(10) is for new line ' Anything typed after single quote is a comment. ' space is shown in bytes. change to KB, MB, GB by dividing 1024

Copy and paste the code. Run it.

C:\scripts>cscript fsdrives.vbs //nologo Number of Drives 3 ----------------------------------------------------------------- C       C:      True                  NTFS    421 GB  195 GB  195 GB D       D:      True    LENOVO  NTFS    28 GB    19 GB    19 GB F       F:      False C:\scripts>

That is the output I get. Your challenge would be to fine tune the code further so that the numbers are aligned below each other. On your machine you may see more or less drives and the numbers different.

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 2–Solution Part 2

Fibonacci Series Solution

wscript.echo "Fibonacci Series" x=1 y=1 wscript.echo 1 wscript.echo 1 for a=3 to 15     z=x+y     x=y     y=z     wscript.echo z next

 

Output

C:\scripts>cscript fibo.vbs //nologo Fibonacci Series 1 1 2 3 5 8 13 21 34 55 89 144 233 377 610

 

An interesting video on Fibonacci Series can be viewed here.

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 2–Solution

The following is the solution of the question in the last post. Printing the prime numbers between 1 and 100. This may not be the best logic, yet it gets what to be done. It is more important to develop a timely solution than an untimely one.

wscript.echo "1" wscript.echo "2" wscript.echo "3" for x=5 to 100 step 2     isprime=0     for z=2 to x-1         if x mod z = 0 then             isprime=1         end if     next     if isprime=0 then         wscript.echo x     end if next

and the output

C:\scripts>cscript prime.vbs //nologo 1 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59 61 67 71 73 79 83 89 97

Some more examples that you should try

1. List the Fibonacci series – first 15 numbers

2. Find the Square root of any number correct to 4 decimal places. (use Newton’s method)

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 2

In any programming language there are three things we need to learn at the earliest.

1. Types of variable

2. Selection Statements

3. Iteration or Loops

Since ours is a “get ready quick” course. We will only try what we think is essential.

1. Variable.

There are no types of variables. What ever you assign the variable takes that values. Unlike in other programming languages you have int, char, fload, date etc. There is nothing here. You can just put any value in any variable. The upside is variable usage is easy. Same variables can be recycled. The downside is explicit conversions are needed everytime a variable of a specific type is needed.

Assume you have a program with the following

i=5 wscript.echo i i="Programs" wscript.echo i

When you run it there is no error.

 

2. Selection statements.

Keeping it simple.

if <condn> then

<statements>

else

<statements>

randomize i=int(rnd * 10) wscript.echo i if i mod 2 =0 then     wscript.echo "Even Number" else     wscript.echo "Odd Number" end if

randomize – resets the seed, so that you get a real random numbers all the time. rnd generates a random number between 0 and 0.999xxx. The int function converts the output to an integer (we don’t need the decimals). The mod is a operation to find the remainder.

The above program prints either even or odd depending on the random number. In the example the program is saved as third.vbs

C:\scripts>cscript third.vbs Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. 7 Odd Number C:\scripts> C:\scripts>cscript third.vbs Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. 1 Odd Number C:\scripts>third Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. 0 Even Number C:\scripts>cscript third.vbs Microsoft (R) Windows Script Host Version 5.8 Copyright (C) Microsoft Corporation. All rights reserved. 6 Even Number C:\scripts>

3. Iteration or Loops

The most convenient loop is the for – next.

An example

wscript.echo "Program 2" for i=1 to 5         wscript.echo i next wscript.echo "Random Numbers" for i = 5 to 1 step -1         randomize         intnum=rnd         wscript.echo int(intnum*10) next

 

A simple program the prints, from 1 to 5. And then random numbers between 0 and 9.

Program 2 1 2 3 4 5 Random Numbers 1 0 8 2 0

Try this exercise.

Print the first 100 prime numbers.

use the concepts learnt.

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 1

Windows Scripting (the normal shell) for Ex VB Programmers - Lesson 1

Good if you know the old Visual Basic

1. How to write your first script. (lets call this as first.vbs)

1. run cmd.exe

2. create a folder called c:\scripts

3. run notepad first.vbs

4. Save and run this file as follows

5. Try to run the file without using cscript and see what you get

6. This is because by default vbs files are executed using wscript

7. what if you wanted to change the default. Do the following

8. What if you wanted to change back the default to wscript

wscript //H:wscript

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