sprintf output in quote marks

Projects Programming
1

Hi,
unfortuantely i require some help getting audio output working with random-track-number filename generation. I'm using TMRpcm library, within code im generating char variable buffer which outputs in filename as it it on sdcard (eg. 1.wav) and here's where trouble begins - function tmrpcm.play(buffer) won't recognize filename because it operates on filename embedded in quotation marks [eg. tmrpcm.play("1.wav") instead of tmrpcm.play(1.wav)].

TLDR: Need help embedding sprintf output filename in quotation marks.

It's probably quite easy to solve, thought after few hours i still can't get it to work. Any help would be much appreciated.

#include <SD.h>                      // need to include the SD library
#define SD_ChipSelectPin 4  //using digital pin 4 on arduino nano 328, can use other pins
#include <TMRpcm.h>           //  also need to include this library...
#include <SPI.h>

TMRpcm tmrpcm;   // create an object for use in this sketch

unsigned long time = 0;

void setup(){

  randomSeed(analogRead(0));
  
  tmrpcm.speakerPin = 9; //5,6,11 or 46 on Mega, 9 on Uno, Nano, etc
  //Complimentary Output or Dual Speakers:
   
  Serial.begin(9600);
  if (!SD.begin(SD_ChipSelectPin)) {  // see if the card is present and can be initialized:
    Serial.println("SD fail");  
    return;   // don't do anything more if not

  }
  else{   
    Serial.println("SD ok");   
  }
  tmrpcm.volume(1);
}


void loop(){  
  char buffer[10];
  int rand = random(1,5);
  Serial.println(rand); //debug
  sprintf(buffer,"%d.wav",rand); 
  Serial.println(buffer); //debug
  
  tmrpcm.play(buffer);
  Serial.println("-------------------------"); //debug
  delay(5000);
  
 }
2

"

3 
sprintf(buffer,"\"%d.wav\"",rand);
4

I would be very surprised if that's the actual problem. Why would it need the file name in quotes? It doesn't need the quotes when it's a string literal. (Those quotes are not part of the string itself.)

5

I'd be surprised too, but that's what the OP asked for, and they didn't post any code (despite this being the programing question section) to indicate otherwise.

7

Whoa, thx for almost instant answers. And yes i do suck at coding, I really thought i nailed it this time, but well u were right, it didn't work as well tho output is within quotes. String var isn't working either - that was my first attempt, tho output was correct the function just didn't deliver. Still have no idea why is that, couse when i input filename directly into function it works.

8

there should be no difference between:

somefunc("file.txt");

and

char filename[32];
strcpy(filename, "file.txt");
somefunc(filename);

if there is, you are doing something wrong. Are you not '\0' terminated?