Why does this take more byte?

Question

I am only replacing a portion of my code where I want to use the first method but as you can see it is making my sketch size little bigger

//if(iBPM >= 40 || iBPM <= 170 )
      {
      char iBPMwav[50];
      String thisString = String(iBPM);
      String stringThree =  "n" + thisString;
      stringThree =  stringThree + ".wav";
      stringThree.toCharArray(iBPMwav, 50); 
      tmrpcm.play(iBPMwav);   
      }

Sketch uses 29678 bytes (100%)

This is simple but at the end, I want to go from the number 40 up to 170, and this is why I want to use the first method.

//if(iBPM >= 40 || iBPM <= 170 )
  {
      if(iBPM == 71)
tmrpcm.play("n71.wav"); 
  else if(iBPM == 72)
tmrpcm.play("n72.wav");
  else if(iBPM == 73)
tmrpcm.play("n73.wav");  
  else if(iBPM == 74)
tmrpcm.play("n74.wav");     
  else if(iBPM == 75)
tmrpcm.play("n75.wav"); 
  else if(iBPM == 76)
tmrpcm.play("n76.wav"); 
  else if(iBPM == 77)
tmrpcm.play("n77.wav"); 
  else if(iBPM == 78)
tmrpcm.play("n78.wav"); 
  else if(iBPM == 79)
tmrpcm.play("n79.wav"); 
  else if(iBPM == 80)
tmrpcm.play("n80.wav"); 
  else if(iBPM == 81)
tmrpcm.play("n81.wav");
  else if(iBPM == 82)
tmrpcm.play("n82.wav");  
  else if(iBPM == 83)
tmrpcm.play("n83.wav");     
  else if(iBPM == 84)
tmrpcm.play("n84.wav"); 
  else if(iBPM == 85)
tmrpcm.play("n85.wav"); 
  else if(iBPM == 86)
tmrpcm.play("n86.wav"); 
  else if(iBPM == 87)
tmrpcm.play("n87.wav"); 
  else if(iBPM == 89)
tmrpcm.play("n89.wav");
  else if(iBPM == 90)
tmrpcm.play("n90.wav");
  else if(iBPM == 91)
tmrpcm.play("n91.wav"); 
  else if(iBPM == 92)
tmrpcm.play("n92.wav");
  else if(iBPM == 93)
tmrpcm.play("n93.wav");  
  else if(iBPM == 94)
tmrpcm.play("n94.wav");     
  else if(iBPM == 95)
tmrpcm.play("n95.wav"); 
  else if(iBPM == 96)
tmrpcm.play("n96.wav"); 
  else if(iBPM == 97)
tmrpcm.play("n97.wav"); 
  else if(iBPM == 98)
tmrpcm.play("n98.wav"); 
  else if(iBPM == 99)
tmrpcm.play("n99.wav");
  else if(iBPM == 100)
tmrpcm.play("n100.wav"); 
  else if(iBPM == 101)
tmrpcm.play("n101.wav"); 
  else if(iBPM == 102)
tmrpcm.play("n102.wav");                                                     
else 
 tmrpcm.play("n170.wav");
}

Sketch uses 29024 bytes (101%)

You are using the String class which is pretty mighty and not light weight. It is always a good idea NOT to use the String class on MCUs. — Kwasmich, Jul 04 '19 at 10:05
Are you aware that iBPM >= 40 || iBPM <= 170 is always true? — Edgar Bonet, Jul 04 '19 at 11:02
Then you should learn what the operators >=, <= and || mean. — Edgar Bonet, Jul 05 '19 at 09:24
@EdgarBonet Yes I did look that up that after you mentioned and learned from somewhere else. Tell me about it what a huge mistake boy ha ha — Noajm IsMy Name, Jul 06 '19 at 21:09

score 2 · Accepted Answer · answered Jul 04 '19 at 10:21

2

I suggest having simpler file names (same size, always 3 digit numbers)

/// Return a text "n000.wav" ... "n255.wav" 
/// depending on the parameter 
char* makeFileName(byte i) {    
  static char name[9] = "nxxx.wav";
  byte digit = i/100;
  name[1] = '0' + digit;
  i -= digit*100; 
  digit = i/10;
  name[2] = '0' + digit; 
  i -= digit*10;
  name[3] = '0' + i;

  return name;
}

answered Jul 04 '19 at 10:21

DataFiddler

1,045
6
14

Looks smart to me. I will try it today. – Noajm IsMy Name Jul 04 '19 at 20:02
Alright, I like your idea.. changing the name of the files will be like loosen flywheel for me. Instead, I made your code into two versions the first for "nxx.wav" and one for "nxxx.wav" – Noajm IsMy Name Jul 05 '19 at 06:37

score 1 · Answer 2 · answered Jul 04 '19 at 12:41

While the Strings class makes a C/C++ program easy to understand and maintain, as stated in the comments, using the Strings class is a memory intensive option which should be should be avoided when memory is in short supply. Such as on the embedded processors used in most Arduino platforms.

Here are 2 examples where Stings is used and not used. Note the reduction from 2326 bytes to 734 bytes of program memory necessary to store the sketch in the embedded processor.

void setup() 
{
}

void loop() 
{
  uint8_t iBPM;
  uint8_t pointer;
  for(iBPM = 40; iBPM <= 170; iBPM++)
  {
    char iBPMwav[50];
    String thisString = String(iBPM);
    String stringThree =  "n" + thisString;
    stringThree =  stringThree + ".wav";
    stringThree.toCharArray(iBPMwav, 50); 
//  tmrpcm.play(iBPMwav);   
  }
}

Sketch uses 2326 bytes (7%) of program storage space. Maximum is 32256 bytes. Global variables use 27 bytes (1%) of dynamic memory...

void setup() 
{
}

void loop() 
{
  uint8_t iBPM;
  uint8_t pointer;
  for(iBPM = 40; iBPM <= 170; iBPM++)
  {
    char iBPMwav[50];
    pointer = 0;
    char temp_str[10];
//  String thisString = String(iBPM);
//  String stringThree =  "n" + thisString;
//  stringThree =  stringThree + ".wav";
//  stringThree.toCharArray(iBPMwav, 50); 
    itoa(iBPM, temp_str, 10);
    if(iBPM < 100)
    {
      strncpy(&iBPMwav[pointer],"n0",2);
      pointer += 2;
      strncpy(&iBPMwav[pointer],temp_str,2);
      pointer += 2;
    }
    else
    {
      strncpy(&iBPMwav[pointer],"n",1);
      pointer += 1;
      strncpy(&iBPMwav[pointer],temp_str,3);
      pointer += 3;
    }
    strncpy(&iBPMwav[pointer],".wav",4);
//  tmrpcm.play(iBPMwav);   
  }
}

Sketch uses 734 bytes (2%) of program storage space. Maximum is 32256 bytes. Global variables use 15 bytes (0%) of dynamic memory...

BTW: String use even more RAM than compiler can see. And String+String is awfully complicated, creating a lot of garbage :) — DataFiddler, Jul 04 '19 at 17:19

Why does this take more byte?

2 Answers2