Adds the value of an expression to the value of a variable and assigns the result to the variable.
result += expression
Using this operator is exactly the same as specifying:
result = result + expression
The underlying subtype of the expressions determines the behavior of the += operator.
| If | Then |
|---|---|
| Both expressions are numeric or Boolean | Add |
| Both expressions are strings | Concatenate |
| One expression is numeric and the other is a string | Concatenate |