Looking for a solution to optimize the program fragment

Using Arduino Programming Questions
1

Hi all.
the program fragment like to set just one mark HIGH and all others LOW, how to optimize it like for-loop?
Thanks
Adam

if (condationA){
  MarkA = 1;
  MarkB = 0;
  MarkC = 0;
  MarkD = 0;
}else if (condationB){
  MarkA = 0;
  MarkB = 1;
  MarkC = 0;
  MarkD = 0;
}else if (condationC){
  MarkA = 0;
  MarkB = 0;
  MarkC = 1;
  MarkD = 0;
}else if (condationD){
  MarkA = 0;
  MarkB = 0;
  MarkC = 0;
  MarkD = 1;
}
2

Give examples of what condationA thru condationD might be.

2 Likes
3

If you’re treating them as separate variables, zero all at the top of the if(), then only set the required 1s in each condition.

Or you could use an array of Marks[] in the same way…
Even a bit array to hold your 0-1 values.

2 Likes
4

Hello shanren

Consider:

// make names
enum Condition {A, B, C, D};
// make variables
int16_t condition;
// make structures
struct MARK
{
  Condition condition;
  int16_t value;
};
MARK mark[] {A, 0, B, 0, C, 0, D, 0};
// make application
void setup()
{
}
void loop()
{
  for (auto &mark_ : mark) condition == mark_.condition ? mark_.value = 1 : mark_.value = 0;
}

Have a nice day and enjoy coding in C++.

1 Like
5 
    MarkA = MarkB = MarkC = MarkD = 0;

    switch (condition) {
    case CondA:
        MarkA = 1;
        break;

    case CondB:
        MarkB = 1;
        break;

    case CondC:
        MarkC = 1;
        break;

    case CondD:
        MarkD = 1;
        break;
    }
4 Likes
6

Do you need 4 separate variables?

Could you just use 1 bit to represent each condition?

uit8_t mark;

:
:

mark =0;

if( conditionA )  mark |= 0x01;
if( conditionB )  mark |= 0x02;
if( conditionC )  mark |= 0x04;
if( conditionD )  mark |= 0x08;

or

struct {
   unsigned int A: 1;
   unsigned int B: 1;
   unsigned int C: 1;
   unsigned int D: 1;
} mark;

: 
: 

if( conditionA )  mark.A = 1;
if( conditionB )  mark.B = 1;
if( conditionC )  mark.C = 1;
if( conditionD )  mark.D = 1;
1 Like
7

Thanks.
They are buttons or touch screen soft buttons.

8

Thanks.
I did this way, but seems something not right in my code or ? I got expected result till I used the way in #1 post.

Sorry, my code don't have " zero all at the top of the if(), " and just zero all at the header config, maybe this is the reason?

Tested the way here can't control individual mark's 0 or 1.

9

Thanks.
I'll check it.
Have a nice day.

10

Thanks.
It works!

11

Thanks.
They are manually controlled buttons.

12 
MarkA=(condationA?1:0);
MarkB=(condationB?1:0);
MarkC=(condationC?1:0);
MarkD=(condationD?1:0);
3 Likes
13

You could treat all the Mark variables as bool, and just have:

MarkA = condationA;
MarkB = condationB;
MarkC = condationC;
MarkD = condationD;

So MarkA will be true or false corresponding to whether the condationA evaluates as true or false, etc ...

1 Like
14

Thanks.
I'll test it.

15

... or force it to be boolean:

MarkA = (bool)condationA;
MarkB = (bool)condationB;
MarkC = (bool)condationC;
MarkD = (bool)condationD;
1 Like
16

a program fragment can't show enough context.

for example instead of MarkA, MarkB, MarkC, MarkD ... consider one Mark[4]
or why 4 variables at all.
in binary that information would fit in a single byte variable also.

1 Like
17

That would be too simple. Just think of it: C++ uses byte for bool. Why would you want to make it smaller?

1 Like
18

On an AVR UNO, RAM is quite precious ...

1 Like
19

conditionA is likely a bool already

2 Likes
20

Indeed it has to be - as it was the condition of an if in the OP:

1 Like