While Loop Condition C++

Question

What does this condition mean in a while loop?

 int x;
 cin >> x;
 while(x) {
   ...
 }

Should probably be `while(cin >> x){`, but cannot tell from such narrow context given. — πάντα ῥεῖ, Jan 08 '16 at 18:43

score 6 · Accepted Answer · answered Jan 08 '16 at 18:42

6

int has an implicit conversion to bool. Basically 0 converts to false, all nonzero values convert to true

So more verbosely, your condition would read

while (x != 0)

answered Jan 08 '16 at 18:42

Cory Kramer

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score 0 · Answer 2 · answered Jan 08 '16 at 21:01

As @CoryKramer says, when you have a condition which only contains a variable, even if is a char, int, float, etc. the value 0 is considered as false, and any other as true. If you are using pointers is the same: the NULL value is considered as false, and any other direction is considered as true.

While Loop Condition C++

2 Answers2