In a “for” statement, should I use `!=` or `<`?

Question

I\'ve seen both of these two for statements:

for(i=0;i<10;i++) 

for(i=0;i!=10;i++)

I know they all stop when i reaches 10 , bu

Answer 1

Both will work in most situations.

If for some reason the body of code executed in the loop changes i to something greater than 10, the first version will stop looping, but the second will execute forever.

Answer 2

The best practice is to use != only with iterators (C++) and < otherwise. Never ever use == or != with floats/doubles. The following loop is an infinite loop:

for (double i = 0.0; i != 1.0; i += 0.1)
    printf("yes, I'm an infinite loop ;)");