// Please enter your birthday in this // format(including spaces): // DD MM YYYY // 22 01 1997 // By @ Michael Xanthopoulos //Converted from C++ to Java by me. import java.util.*; public class DayOfBirth { public static void main(String args[]) { int DD = 32, MM = 13, YYYY = -1, NYYYY, NMM, IDAY, day, flag = 0; String month[] = {"January","February","March","April","May","June","July","August","September","October","November","December"}; Scanner in = new Scanner (System.in); try { System.out.println("Enter the Date in the Format DD MM YYYY."); DD = in.nextInt(); MM = in.nextInt(); YYYY = in.nextInt(); }catch(Exception e){ System.out.println("Invalid Input"); System.exit(0); } if(DD <= 0) { //Error Message: User has given invalid input for "Days" & "Months" fields if(MM <= 0) { System.out.println(" We don't have negative or null days and months. "); System.out.println(" Try again! "); System.exit(0); } //Error Message: User has given invalid input for "Days" field System.out.println(" We don't have negative or null days. "); System.out.println(" Try again! "); System.exit(0); } if(MM <= 0) { //Error Message: User has given invalid input for "Months" field System.out.println(" We don't have negative or null months. "); System.out.println(" Try again! "); System.exit(0); } if(DD > 31 || MM > 12 || YYYY <= 0) { if(DD > 31 && MM > 12) { //Error Message: User has given invalid input for "Days", "Months" & "Years" fields if(YYYY <= 0) { System.out.println(" We have 12 months, the days of a month are up to 31 "); System.out.println(" and a year should be a positive number. "); System.out.println(" Try again! "); } //Error Message: User has given invalid input for "Days" & "Months" fields else { System.out.println(" We have 12 months and "); System.out.println(" the days of a month are up to 31. "); System.out.println(" Try again! "); } } else if(DD > 31 && MM <= 12) { //Error Message: User has given invalid input for "Days" & "Years" fields if(YYYY <= 0) { System.out.println(" The days of a month are up to 31 and "); System.out.println(" a year should be a positive number. "); System.out.println(" Try again! "); } //Error Message: User has given invalid input for "Days" field else { System.out.println(" The days of a month are up to 31. "); System.out.println(" Try again! "); } } else if(DD <= 31 && MM > 12) { //Error Message: User has given invalid input for "Months" & "Years" fields if(YYYY <= 0) { System.out.println(" We have 12 months and "); System.out.println(" a year should be a positive number. "); System.out.println(" Try again! "); } //Error Message: User has given invalid input for "Months" field else { System.out.println(" We have 12 months. "); System.out.println(" Try again! "); } } //Error Message: User has given invalid input for "Years" field else if(DD <= 31 && MM <= 12 && YYYY <= 0) { System.out.println(" A year should be a positive number. "); System.out.println(" Try again! "); } System.exit(0); } switch(MM) { case 2: if((YYYY % 400) == 0 || ((YYYY % 4) == 0 && (YYYY % 100) != 0)) { //Error Message: User has requested an invalid day for the month "February" // and the requested "Year" is a leap year. if(DD > 29) { System.out.println(" The year " + YYYY + " is a leap year. "); System.out.println(" So, February has up to 29 days. "); System.out.println(" Try again! "); System.exit(0); } } else { //Error Message: User has requested an invalid day for the month "February" // and the requested "Year" is not a leap year. if(DD > 28) { System.out.println(" The year " + YYYY + " isn't a leap year. "); System.out.println(" So, February has up to 28 days. "); System.out.println(" Try again! "); System.exit(0); } } break; case 4: //Error Message: User has requested an invalid day for the month "April" if(DD > 30) { System.out.println(" April has up to 30 days. "); System.out.println(" Try again! "); System.exit(0); } break; case 6: //Error Message: User has requested an invalid day for the month "June" if(DD > 30) { System.out.println(" June has up to 30 days. "); System.out.println(" Try again! "); System.exit(0); } break; case 9: //Error Message: User has requested an invalid day for the month "September" if(DD > 30) { System.out.println(" September has up to 30 days. "); System.out.println(" Try again! "); System.exit(0); } break; case 11: //Error Message: User has requested an invalid day for the month "November" if(DD > 30) { System.out.println(" November has up to 30 days. "); System.out.println(" Try again! "); System.exit(0); } break; } if(MM <= 2) { NYYYY = YYYY - 1; NMM = 0; } else { NYYYY = YYYY; NMM = (4 * MM + 23) / 10; } //Calculating the day IDAY = 365 * YYYY + DD + 31 * (MM - 1) - NMM + (NYYYY / 4) - ((3 * ((NYYYY / 100) + 1) / 4)); day = IDAY % 7; //This 'flag' is used for displaying the right ending after the numbers if(DD != 11 && DD != 12 && DD != 13) flag = DD % 10; switch(day) { case 0: System.out.print(" You were born on Saturday, "); break; case 1: System.out.print(" You were born on Sunday, "); break; case 2: System.out.print(" You were born on Monday, "); break; case 3: System.out.print(" You were born on Tuesday, "); break; case 4: System.out.print(" You were born on Wednesday, "); break; case 5: System.out.print(" You were born on Thursday, "); break; case 6: System.out.print(" You were born on Friday, "); break; } if(flag == 1){ System.out.print(DD + "st of "); } else if(flag == 2){ System.out.print(DD + "nd of "); } else if(flag == 3){ System.out.print(DD + "rd of "); } else{ System.out.print(DD + "th of "); } System.out.print(month[MM-1] + " of " + YYYY + "!"); } }

Find The Day of the Week You Were Born On! (JAVA)