Arduino, Pad Integers for Formatted Printing

pad.ino

/* 
auth: mmasnion
desc: get zero-padded string for numbers under 50,000
*/

int testNumber = 70;

void setup() {
  Serial.begin(9600);
}

void loop() {
  String paddedNumber = getPadded(testNumber); //converts to char
  Serial.println(paddedNumber);
  delay(1000);
}

String getPadded(int num) {
  char buff[6];
  char padded[7];
  
  //sprintf function will convert the long to a string
  sprintf(buff, "%.5u", num); // buff will be "01238"

  padded[0] = buff[0];
  padded[1] = buff[1];
  padded[2] = buff[2];
  padded[3] = buff[3];
  padded[4] = buff[4];
  padded[5] = buff[5];
  padded[6] = '\0'; // The terminating NULL

  return String(padded);
}