Testing for loop termination using an equality operator (== and !=) is dangerous, because it could set up an infinite loop. Using a broader relational operator instead casts a wider net, and makes it harder (but not impossible) to accidentally write an infinite loop.

Noncompliant Code Example

for (int i = 1; i != 10; i += 2)  // Noncompliant. Infinite; i goes from 9 straight to 11.
{
  //...
}

Compliant Solution

for (int i = 1; i <= 10; i += 2)  // Compliant
{
  //...
}

Exceptions

Equality operators are ignored if the loop counter is not modified within the body of the loop and either:

Equality operators are also ignored when the test is against null.

for (int i = 0; arr[i] != null; i++) {
  // ...
}

for (int i = 0; (item = arr[i]) != null; i++) {
  // ...
}

See