12.1.4 Operators
- Jessica Reyes (Unlicensed)
- Scott Fredericks (Unlicensed)
There are three types of operators that can be used in programs: Calculation Operator, Logical/Comparative Operator, and Others.
(1) Calculation Operator
In the table below, the calculation result assumes variable A is 3 (0000 0000 0000 0011), and the variable B is 4 (0000 0000 0000 0100).
Remainder calculation and all Bitwise calculations will be performed with 32-bit integer data.
Operator | Function | Example | Description |
~ | Bitwise invert | ~A | Each bit of A (0000 0000 0000 0011b) is inverted. The result is 1111 1111 1111 1100b. |
+ | Addition | A+B | Adds A and B. The result is 7. |
- | Subtraction | A –B | Subtracts B from A. The result is -1. |
* | Multiplication | A*B | Multiplies A and B. The result is 12. |
/ | Division | A / B | Divides A with B. The result is 0.75. |
% | Remainder | A % B | Indicates the remainder from the division of A with B. The result is 3. |
& | Bitwise AND | A & B | Bitwise logical AND calculation of A and B. The result is 0. |
| | Bitwise OR | A | B | Bitwise logical OR calculation of A and B. The result is 0111b (= 7). |
^ | Bitwise XOR | A ^ B | Bitwise logical XOR calculation of A and B. The result is 0111b (= 7). |
<< | Bitwise Shift Left | A << B | Shifts the bits of A to the left as much as B. The rightmost part is filled with 0. The result is 0011 0000b (= 48). |
>> | Bitwise Shift Right | A >> B | Shifts the bits of A to the right as much as B. The leftmost part is filled with 0. The result is 0. |
(2) Logical/Comparative Operator
In the table shown below, the calculation result assumes that variable A is 1 (True) and the variable B is 0 (False). In Xpanel, the values other than 0 are all processed as True. Only 0 is recognized as False.
When the calculation result is true, the result is always 1.
Operator | Function | Example | Description |
&& | Logical AND | A && B | If A and B are true, the result is 1. In other cases, the result is 0. |
|| | Logical OR | A || B | If A and B are false, the result is 0. In other cases, the result is 1. |
< | Less than | A < B | If A is smaller than B, the result is 1. In other cases, the result is 0. |
> | Greater than | A > B | If A is greater than B, the result is 1. In other cases, the result is 0. |
<= or =< | Less than or equal to | A <= B | If A is smaller than or equal to B, the result is 1. In other cases, the result is 0. |
>= or => | Greater than or equal to | A >= B | If A is greater than or equal to B, the result is 1. In other cases, the result is 0. |
== | Equal to | A == B | If A is equal to B, the result is 1. In other cases, the result is 0. |
!= | Is not equal to | A != B | If A is not B, the result is 1. In other cases, the result is 0. |
(3) Other Operator
Operator | Function | Example | Description |
= | Store | A = B | Stores the value B to A and uses it as a result. |
The Store (=) operator can be used consecutively.
A = B = C;
In this case, the value of A and B will be set as C. In other words, the value at the rightmost side of the operator will be treated as the result value of the “=” operation. The example mentioned above will be processed internally in the program as shown below.
B ← C
A ← B
| The features of the “=” operator may cause a program error that cannot be detected as shown below. Even if the values of A and B are not equal, the operation result of the IF statement can be True. This operation may cause an unwanted B value to be stored in A. //=================== // A Program Error That Cannot Be Detected //=================== If (A=B) // Mis-entry of A==B, checking if the value of A and B are the same. { … } |