Why do c++ programmers use != instead of <

Question

In c++ primer, pg 95 the author says that c++ programmers tend to use != in preference of < when writing loops.

for (vector::size_type i = 0;          


        

Answer 1

Think of the case when one have to increment by lets say 3 instead of 1.

for (vector::size_type i = 0; i != 10; i+=3)

This will run forever since it will skip 10 and go to 12 instead and increment forever.

for (vector::size_type i = 0; i < 10; i+=3) 

This will work fine in this case too. So != is not always a good choice.