batch-file Bugs in cmd.exe processor Parentheses Confusion
Example
From this website, the OP has noticed a problem.
Cause
Consider the following code snippet.
if 1==1 (
set /a result = 2*(3+4)
)
At your first glance, you may think CMD.exe would process it like so:
- The condition is true, execute code block
- Set variable result's value to
14 - Continue
However, CMD.exe process like so:
- The condition is true, execute code block
- Calculate
2*(3+4, the)after 4 is processed at the end ofifcode block - A random
)has appeared!
The second step would return Unbalanced parentheses error.
Solution
According to a German CMD.exe's set /?, we would need to quote arithmetic operations. Here's an example.
| Previous | Result |
|---|---|
set /a result=2+5*4 | set /a result="2+5*4" |
By the way, according to an English CMD.exe set /?, quotes are required if logical or modulus operators are present in the expression(although this is not a must-do step).
