-999 ?

[jchase520]

Ok I'm reading my C++ book I got in college, I'm on chapter 8, about 500 pages in. The book is talking about a program that calculates grades from 2 input files then outputs them back to a file. It uses

while (score != -999)

my question, what is the significance of -999 ? I know it must be the return of something, a error from something or whatever, i just can't remember what.

[Disch]

Probably just a "magic number" that escapes the loop.

The number itself has no significance other than that it's used to exit the loop. The program probably explicitly sets score to -999 somewhere when it wants the loop to stop.

It's unclear (hence your quesiton), which is why usage of magic numbers is not recommended.

[jchase520]

I guess it was supposed to be a sentinel controlled while loop

[buffbill]

.........meaning that somewhere within the loop body there will be a direction:

cout<<"Enter a number n  (-999 to quit);
cin>>n;