new flash checksum program

PROGMEM char txt[] = "The Greek mathematician Diophantus The Greek mathematician Diophantus has traditionally been known as the 'father of algebra' but in more recent times there is much debate over whether al-Khwarizmi, who founded the discipline of al-jabr, deserves that title instead.[10] Those who support Diophantus point to the fact that the algebra found in Al-Jabr is slightly more elementary than the algebra found in Arithmetica and that Arithmetica is syncopated while Al-Jabr is fully rhetorical.[11] Those who support Al-Khwarizmi point to the fact that he introduced the methods of 'reduction' and 'balancing' (the transposition of subtracted terms to the other side of an equation, that is, the cancellation of like terms ";

void setup() {
  Serial.begin(9600);
  Serial.println("welcome");
}

void loop() {
  int checksum = 0;
  checksum = 0;
  Serial.println(0);
  for(int i=0; i<sizeof(txt); i++) {
    checksum+=txt[i];
    Serial.print(txt[i]);
  }
  Serial.println(checksum);
}