import java.util.Calendar; import java.util.HashMap; import java.util.Scanner; /************************************** How to use: Enter a date like: [day] [month] [year] EXAMPLE: 01 01 2000 **************************************/ public class DaysAgo{ static boolean IsLeapYear(int y){ boolean bl = false; if((y%4)==0){ bl = true; } return bl; } static int MonthSize(int m, int y){ int size = 0; HashMap monthsize = new HashMap(); monthsize.put(1, 31); monthsize.put(2, 28); monthsize.put(3, 31); monthsize.put(4, 30); monthsize.put(5, 31); monthsize.put(6, 30); monthsize.put(7, 31); monthsize.put(8, 31); monthsize.put(9, 30); monthsize.put(10, 31); monthsize.put(11, 30); monthsize.put(12, 31); if (IsLeapYear(y) && m == 2){ size = 29; }else { size = monthsize.get(m); } return size; } static int GetDayCount(int curday, int curmonth, int curyear, int gday, int gmonth, int gyear){ int calc = 0; // calculate year days if (gmonth < curmonth){ for (int c = (gyear); c < curyear; c ++){ if (IsLeapYear((c))){ calc = calc + 366; }else{ calc = calc + 365; } } }else if (gmonth == curmonth){ if (gday <= curday){ for (int c = (gyear); c < curyear; c ++){ if (IsLeapYear((c))){ calc = calc + 366; }else{ calc = calc + 365; } } } }else{ for (int c = (gyear+1); c < curyear; c ++){ if (IsLeapYear((c))){ calc = calc + 366; }else{ calc = calc + 365; } } } if (((curyear - gyear)/ 100) >= 1){ calc = calc - ((curyear - gyear)/100); } // calculate month days if (gmonth > curmonth){ for (int c = gmonth; c <= 12; c++){ calc = (calc + MonthSize(c, (curyear-1))); } for (int c = 1; c < curmonth; c++){ calc = (calc + MonthSize(c, curyear)); } }else{ if (gday > curday){ for (int c = gmonth; c < (curmonth-1); c ++){ calc = (calc + MonthSize(c, curyear)); } }else{ for (int c = gmonth; c < curmonth; c ++){ calc = (calc + MonthSize(c, curyear)); } } } // calculate days if (gday > curday){ if (curmonth == 1){ for (int c = gday; c < MonthSize(12, curyear-1); c++){ calc = calc + 1; } }else{ for (int c = gday; c < MonthSize(curmonth-1, curyear); c++){ calc = calc + 1; } } for (int c = 1; c <= curday; c++){ calc = calc + 1; } }else{ for (int c = gday; c < curday; c++){ calc = calc + 1; } } return calc; } public static void main(String[] args) { try{ String[] days = {"", ""}; int currentyear = Calendar.getInstance().get(Calendar.YEAR); int currentmonth = (Calendar.getInstance().get(Calendar.MONTH) + 1); int currentday = Calendar.getInstance().get(Calendar.DAY_OF_MONTH); int inputday = 0; int inputmonth= 0; int inputyear = 0; Scanner inp = new Scanner(System.in); String[] input = inp.nextLine().split(" "); int inpn[] = {Integer.parseInt( input[0] ), Integer.parseInt( input[1] ), Integer.parseInt( input[2] )}; boolean cont = true; if (((Integer.parseInt( input[0] )) < 1) || ((Integer.parseInt( input[0] )) > 31)){ System.out.println("Please enter valid day. 1 | 31"); cont = false; } else{ inputday = Integer.parseInt( input[0] ); } if (((Integer.parseInt( input[1] )) < 1) || ((Integer.parseInt( input[1] )) > 12)){ System.out.println("Please enter valid month. 1 | 12"); cont = false; } else{ inputmonth = Integer.parseInt( input[1] ); } if (((Integer.parseInt( input[2] )) < 1) ){ System.out.println("Please enter valid year. 1 | " + currentyear); cont = false; } else{ inputyear = Integer.parseInt( input[2] ); } if (inpn[2] > currentyear){ System.out.println("Please enter day in the past."); cont = false; }else if (inpn[2] == currentyear){ if (inpn[1] > currentmonth){ System.out.println("Please enter day in the past."); cont = false; }else if (inpn[1] == currentmonth){ if (inpn[0] > currentday){ System.out.println("Please enter day in the past."); cont = false; }else if (inpn[0] == currentday){ System.out.println("You entered today!"); cont = false; }else if (inpn[0] < currentday){ cont = true; } } } if (cont){ System.out.println("\n\n\n\n" + inputday + "/" + inputmonth + "/" + inputyear + " Was:"); System.out.println("-----------------"); System.out.println(GetDayCount(currentday, currentmonth, currentyear, inputday, inputmonth, inputyear)); System.out.println("-----------------"); System.out.println("Days ago. \n"); } }catch(Exception e){ System.out.println("Error, Please enter input as '[day] [month] [year]' EXAMPLE: 01 01 2000"); } } }

DaysAgo Calculator