The <> operator takes two operands and compares them for equality. If the operands are numeric then the numeric type conversion rules are applied before the comparision is done. If the operands are of char type or of string type then the char/string type conversion rules are applied before the comparision is done. The result of this operation is of boolean type, and is true if the operands are not equal, and false otherwise.
23 <> 23 results in false
-23 <> -23 results in false
23 <> 23.0 results in false
23.0 <> 23 results in false
23 <> -23 results in true
2 <> 3 results in true
3 <> 2 results in true