Better to use parentheses in the macro so that the macro can be used "normally". You wouldn't normally have to bracket a subexpression so requiring the programmer to remember for SQR that they have to do
Code:
`225/(SQR(15))`
will lead to bugs because you don't remember stuff like this.

So define the macro as
Code:
`#define SQR(x) ( (x) * (x) )`
so that it can be used normally, i.e.
Code:
```225/SQR(15)
225/SQR(7+8)```
etc.
The brackets around the individual x's mean you can put subexpressions into SQR. Without them, the second would be substituted as:
Code:
`225/(7+8*7+8)`
Of course you always have to be very careful with side effect operators. This won't have the expected result:
Code:
```int i=15;
int j=225/SQR(i++);```
What's i? 16? Nope. No amount of bracketing will fix this, which is why we make macros upper case. And relying on this is definitely a bad idea, cos if some smart alec rewrites SQR as
Code:
`#define SQR(x) (pow((x),2))`
then i will be 16 and not 17 as you expected.
Scripting like this