Warning 501. Assignment within conditional. Did you mean == instead of = ?

You attempted to do assignment inside if/while/for statements or inside IIF function. This may be a mistake because chances are that you meant to compare numbers not to assign them. Remember that == is equality check, not =. By using = you don't compare but assign a value to variable. If you really mean to assign inside conditional statement use extra braces.

if( x = 5 ) // warning, you are assigning 5 to variable x
{

}

if( x == 5 ) // correct - you probably meant to COMPARE instead (note == operator)
{

}