Dfyjkt

The following question came to my mind:

Is there any difference between these two ways of running code?

Perhaps in memory management?

int main()
 int counter = 1;
 while(1)
 int arr_one[3] = 0, 1, 2 ;
 int arr_two[3] = 3, 4, 5 ;
 int arr_three[3] = 6, 7, 8 ;
 if(counter == 1)
 for(int i = 0; i < 2; i++) printf("%dn", arr_one[i]); 
 
 if(counter == 2)
 for(int i = 0; i < 2; i++) printf("%dn", arr_two[i]); 
 
 if(counter == 3)
 for(int i = 0; i < 2; i++) printf("%dn", arr_three[i]); 
 
 if(counter >= 4) counter = 1; else counter++; 
 
 return 0;

//

int main()
 int counter = 1;
 while(1)
 if(counter == 1)
 for(int i = 0; i < 2; i++) 
 int arr_one[3] = 0, 1, 2 ;
 printf("%dn", arr_one[i]); 
 
 
 if(counter == 2)
 for(int i = 0; i < 2; i++) 
 int arr_two[3] = 3, 4, 5 ;
 printf("%dn", arr_two[i]); 
 
 
 if(counter == 3)
 for(int i = 0; i < 2; i++) 
 int arr_three[3] = 6, 7, 8 ;
 printf("%dn", arr_three[i]); 
 
 
 if(counter >= 4) counter = 1; else counter++; 
 
 return 0;

//
This is a simplified version of code, which I am using.

Because I'm running the code on an Arduino, as well as with larger arrays, memory is pretty tight. Currently I have the code as shown in the first example, because I haven't read a lot about how C works at its heart.
I hope you could help me out!
Thanks in advance!

Strictly speaking, C doesn't even have a stack, however most implementation use one, and yours likely does.

That being said, it's best to restrict variables to the innermost scope needed to use them. That way, they don't consume stack space longer than needed and they aren't visible to scopes that don't need them.

So your second approach is preferable.

The C standard does not contain such information. The standard sets a number of rules that determines the output of the program. The standard doesn't care how that output is obtained, how much memory is used, how long time it takes and so on...

So your question can't be answered in general. Instead it depends on the platform used and compiler used.

Modern compilers are very good at optimizing the code so it's nearly impossible to predict whether a specific way of writing C code will improve the resulting program.

The best advice is to write your code in an easy to understand way and let the compiler do the optimization. If performance turns out to be bad, profile the code to find bottle necks.

On arduino, better get some very optimized code. It's not an Atari 2600, okay, but still.

Here is a little code that could save you much space (note that this code will resolve what your post says. It might not work for you).

int main() 
 int counter = 0;
 int arr[3] = 0, 1, 2;
 if (counter < 3) 
 for (int i = 0; i < 2; i++)
 printf("%dn", arr[i] + 3 * counter);//better replace 3 with arr lenth.
 counter++;
 else
 counter = 1;