Math on batch (win)

Question

I am developing a CMD batch. I want to do some math in it. This formula: (x+1)100:y

So in batch, x = %x%, and y = %y%. I know how to set the variables. Now, how can batch calculate this? (WINDOWS CMD)

Do I need something extra?

(I need this to be available to users of Windows XP to 7.)

Answer 1

The set command supports some limited calculation. In your case, you want: set /a result=(100*x)/y

Run set /? to see full documentation on what is supported. The /a switch does automatic variable substitution, so you can use x instead of %x%.

Answer 2

@echo off

set x=42
set y=5

set /a z = 100 * x / y

echo %z%

The set /a command allows you to assign the result of a mathematical expression to a variable (at that, the %'s around variable names in these expressions aren't required). See set /? for the list of supported operators and details.

Note that Windows batch files don't support floating-point arithmetic, so if an expression result is a fractional number, only the integer part will be counted. For example, 3/2 evaluates as 1 and 2/3 as 0.

Answer 3

DON'T do maths in batch. If you are doing percentage, you might have decimals and batch doesn't support decimals.(floating). Use vbscript or something better.

save the below as caculate.vbs

Set objFS=CreateObject("Scripting.FileSystemObject")
Set objArgs = WScript.Arguments
x = objArgs(0)
y = objArgs(1)
WScript.Echo ( x + 1 ) * 100  / y

and on command line

c:\test> cscript //nologo calculate.vbs 4 5

Answer 4

• set /a (any arithmatic)
• set /a 2+2 adding
• set /a 2-2 subtracting
• set /a 2*2 multiplying
• set /a 2/2 deviding
• set /a 2^2 exponet

use brackets and parentheses to show the properties of the equations for ex. 2(2+2)=8 Shows distributive property.