Seconds to time

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1

I have found some code in the forum to convert from seconds to time. I make a function from it. But it will not compile.

  1. Why can't I return hrMinSec? What to change? I want to get the string out of the function.
  2. Does the sec %= 60 format the seconds with two characters?
char secondsToHMS(unsigned int seconds, const char ms){
  unsigned int tme=0;
  if(ms == 'j'){                          // If value is millis (milliseconds)
    tme = seconds / 1000;
  } else {
    tme = seconds;
  }
  int hr = tme/3600;                          //Number of seconds in an hour
  int mins = (tme-hr*3600)/60;              //Remove the number of hours and calculate the minutes.
  int sec = tme-hr*3600-mins*60;            //Remove the number of hours and minutes, leaving only seconds.
  sec %= 60;
  mins %= 60;
  hr %= 24;

  String hrMinSec = (String(hr) + ":" + String(mins) + ":" + String(sec));  //Converts to HH:MM:SS string. This can be returned to the calling function.
  Serial.print("String Time: ");Serial.println (hrMinSec);
  return hrMinSec;
}
2

This states that the function returns a single character, not a String.

If you take a look at the error message, you should see some statement to that effect.

3

I have already tried that but I get this fault:

Compilation error: cannot convert 'StringSumHelper' to 'char' in initialization

4

Can you guess what that means, based on my comment?

5

If you would post the entire code, or reduced complete sketch illustrating the problem, and any error message, there would be less guessing and a faster time to solving this.

Without seeing more, just making the return type of secondsToHMD be String instead of char would get you going.

a7

6

Ahhh I changed to function to be a String. Then it works.

What is the difference between char and String? Is char only one character?

1 Like
7

There is a vast difference between data type "char" and a String object, a fundamental aspect of the C/C++ programming language.

If you are using AVR based Arduinos (Uno, etc.), avoid using Strings, as they cause memory problems and program crashes.

8

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