Changing a variable name in a loop

Using Arduino Programming Questions
1

Hey all,

I'm fairly new to working with Arduino and I'm working on a project to Mod my r/c transmitter. I've got my program working so far but was hoping for some help on optimizing the code. I'd like to put this into a for loop such that it continues to look for arrays until it reaches a programmed integer limiting the number of arrays. I can write a for loop, but I'm having a hard time figuring out how to change the selected array each time it iterates.

TLDR: I want a for loop to also loop through char variables array1, array2, array{number specified in a int}

    if (arrayselect == 1) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array1[n];
      }
      }
    if (arrayselect == 2) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array2[n];
      }
      }
    if (arrayselect == 3) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array3[n];
      }
      }
    if (arrayselect == 4) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array4[n];
      }
      }
    if (arrayselect == 5) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array5[n];
      }
      }
    if (arrayselect == 6) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array6[n];
      }
      }
2

Sounds like you're looking for a two-dimensional array.

3

I think that maybe it :slight_smile:

I'm quite familiar with the concept in Matlab, but I've never tried it in C. I'll take a stab at it, thank you.

4

Either 2D-array or nested loop, try something of that arrangement:

#define SIZE(arg) return (sizeof(arg)\sizeof(arg[0]))
for(int i=0;i<SIZE(arraytop);i++ ){
if (arrayselect == 1){
 for ((int j=0;j<SIZE(array1);j++ )){
     arraytop[i]=array1[j];
}
}
if(if (arrayselect == 2){
 for ((int j=0;j<SIZE(array2);j++ )){
     arraytop[i]=array2[j];
}
.
.
.
.
}
5

This demos a concept of using a table/array of pointers to your arrays and using arrayselect to select which one will be copied to arraytop.

It also uses memset and memcpy. If you're not familiar with these look em up :slight_smile:

#define ARRAY_SIZE  22

//define the "top" array
byte
    ArrayTop[ARRAY_SIZE];

//define each of the "sub" arrays
byte
    Array1[ARRAY_SIZE],
    Array2[ARRAY_SIZE],
    Array3[ARRAY_SIZE],
    Array4[ARRAY_SIZE],
    Array5[ARRAY_SIZE],
    Array6[ARRAY_SIZE];

//create an array of pointers to arrays here. Each entry will be a pointed the "sub" arrays
//declared above
const byte 
    *Arrays[6] =
    { 
        Array1,
        Array2,
        Array3,
        Array4,
        Array5,
        Array6
    };

//and an array select variable for demo purposes
int
    arrayselect;

void setup() 
{
    //fill the arrays with different data to illustrate concept
    for( int i=0; i<6; i++ )
        memset( Arrays[i], i, ARRAY_SIZE );

    //serial port
    Serial.begin(9600);

    //init array select
    arrayselect = 0;
    
}//setup

void loop() 
{
    //this copies ARRAY_SIZE bytes from the Array pointed to by Arrays[arrayselect] to ArrayTop
    //a little less clunky than a million for loops and if statements
    memcpy( ArrayTop, Arrays[arrayselect], ARRAY_SIZE );

    //for proof, print out the contents of ArrayTop each pass
    for( int i=0; i<22; i++ )
        Serial.print( ArrayTop[i], DEC );Serial.print(" ");

    Serial.println();

    //bump the arrayselect value, making sure we remain from 0-5 (valid #)
    arrayselect++;
    if( arrayselect == 6 )
        arrayselect = 0;

    //make it human readable
    delay(1000);
        
}//loop
6

While you guys were writing I took my stab at multi dimensional arrays, I'm certain it won't work, but here it is. Was I on the track?

// cut from setup
int nummodes = 6;     // number of possible flight modes

char array1[nummodes][23]={"   Stabilize          "},{"  Auto Horizon        "},{"Return to Launch      "},{"    Mission           "},{"     Loiter           "},{"  Auto Horizon        "}; 

char arraytop[23];
char arraybottom[23];

int n;
int i;

[hr]

// cut from loop

for (int t = 1; t < nummodes + 1; t++){
  if (arrayselect == t) 
    {
       for (n = 0; n < 22; n++) 
      {
        arraytop[n]=array1[t][n];
      }
      }
  
}
7

Thank you all for your help! I'll take a try at what you all said. Once again, VERY novice at C. So please be patient :confused: