decToOctal method
Calculate and return the octal integer value of this integer
Implementation
int decToOctal(){
if(this < 0){
throw "Only positive integers can be converted into octal form using this library";
}
//Use a process similar to converting to hex but with base 8(octal)
String octal = "";
int divisionResult = this;
do{
octal = (divisionResult % 8).toString() + octal;
divisionResult = (divisionResult / 8).floor();
}while(divisionResult != 0);
return int.parse(octal);
}