Merge pull request #4032 from E7-87-83/newt

Practice date and time stuff

9 files changed, 230 insertions, 0 deletions

diff --git a/challenge-013/cheok-yin-fung/README.md b/challenge-013/cheok-yin-fung/README.md
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+Goals:
+  
+- Java: Get familiar with the Date and Time API, 
+- Perl: Get familiar with Time::Piece (and Time::Seconds) module, especially the strftime and strptime methods
+
+attempt on 9th May, 2021
diff --git a/challenge-013/cheok-yin-fung/java/LastFriday.java b/challenge-013/cheok-yin-fung/java/LastFriday.java
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+++ b/challenge-013/cheok-yin-fung/java/LastFriday.java
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+// The Weekly Challenge - 013 
+// Task 1 Last Friday
+// attempt: May 09th, 2021
+// from: C.-Y. Fung
+// Usage: java LastFriday [year]
+import java.time.LocalDate;
+import java.time.YearMonth;
+import java.time.DayOfWeek;
+public class LastFriday 
+{
+    public static void main(String[] args) 
+    {
+        int year = 2008;   // default value
+        if (args.length != 0) 
+            year = Integer.parseInt(args[0]);
+        if (year < 1900) {
+            System.out.println("Sorry, it's too long ago.");
+            System.exit(0);
+        }
+        System.out.println("Year: " + year + "\n");
+        for (int month = 1; month <= 12; month++) {
+            YearMonth temp = YearMonth.of(year, month);
+            LocalDate target = 
+              LocalDate.of(year , month , temp.lengthOfMonth());
+            while ( target.getDayOfWeek() != DayOfWeek.FRIDAY ) {
+                target = target.minusDays(1);
+            }
+            System.out.println(target);
+        }
+    }
+}
diff --git a/challenge-013/cheok-yin-fung/perl/ch-1.pl b/challenge-013/cheok-yin-fung/perl/ch-1.pl
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+++ b/challenge-013/cheok-yin-fung/perl/ch-1.pl
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+#!/usr/bin/perl
+# The Weekly Challenge - 013
+# Task 1 Last Friday
+# attempt: May 09th, 2021
+# from: C.-Y. Fung
+# Usage: ch-1.pl [year]
+# Java correspondence: LastFriday.java
+use Time::Piece;
+use Time::Seconds;
+use strict;
+use warnings;
+
+my $year = $ARGV[0] || 2008;
+die "Sorry, it's too long ago." if $year < 1900;
+print "Year: $year\n\n";
+
+for my $month (1..12) { 
+    my $first_day_of_nmonth = ($month != 12) ? 
+         Time::Piece->strptime($year."-".($month+1)."-01", "%Y-%m-%d")
+       : Time::Piece->strptime(($year+1)."-01-01", "%Y-%m-%d");
+
+    my $target_day = ($first_day_of_nmonth -= ONE_DAY);
+    while ($target_day->day_of_week != 5) {
+        $target_day -= ONE_DAY;
+    }
+    print($target_day->strftime("%Y-%m-%d"), "\n");
+}
diff --git a/challenge-019/cheok-yin-fung/README.md b/challenge-019/cheok-yin-fung/README.md
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+++ b/challenge-019/cheok-yin-fung/README.md
@@ -0,0 +1,6 @@
+Goals:
+  
+- Java: Get familiar with the Date and Time API, 
+- Perl: Get familiar with Time::Piece (and Time::Seconds) module, especially the strftime and strptime methods
+
+attempt on 9th May, 2021
diff --git a/challenge-019/cheok-yin-fung/java/FiveWeekends.java b/challenge-019/cheok-yin-fung/java/FiveWeekends.java
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+++ b/challenge-019/cheok-yin-fung/java/FiveWeekends.java
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+// The Weekly Challenge - 019
+// Task 1 Five Weekends
+// attempt: May 09th, 2021
+// from: C.-Y. Fung
+// Usage: java FiveWeekends [year]
+import java.time.LocalDate;
+import java.time.DayOfWeek;
+import java.time.Month;
+
+public class FiveWeekends
+{
+    public static void main(String[] args) 
+    {
+        int[] months = new int[] {1, 3, 5, 7, 8, 10, 12};
+
+        for (int i = 1900; i <= 2019; i++)
+            for (int M: months)
+                if (LocalDate.of(i,M,1).getDayOfWeek() == DayOfWeek.FRIDAY)
+                    System.out.println(i+" "+ Month.of(M));
+
+    }
+}
diff --git a/challenge-019/cheok-yin-fung/perl/ch-1.pl b/challenge-019/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..2dd7290a3a
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+++ b/challenge-019/cheok-yin-fung/perl/ch-1.pl
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+#!/usr/bin/perl
+# The Weekly Challenge - 019
+# Task 1 Five Weekends
+# Task Statement:
+#   Write a script to display months 
+#   from the year 1900 to 2019 where you find 5 weekends 
+#   i.e. 5 Friday, 5 Saturday and 5 Sunday.
+# attempt: May 09th, 2021
+# from: C.-Y. Fung
+# Java correspondence: FiveWeekends.java
+use Time::Piece;
+use strict;
+use warnings;
+
+my @months = (1, 3, 5, 7, 8, 10, 12);
+
+sub isFridayStart {
+    my $year = $_[0];
+    my $month = $_[1];
+    return
+      Time::Piece->strptime($year."-".$month."-01", "%Y-%m-%d")
+        ->day_of_week == 5;
+}
+
+for my $i (1900..2019) {
+    for my $j (@months) {
+        if (isFridayStart($i, $j)) {
+            print Time::Piece->strptime($i."-".$j."-01", "%Y-%m-%d")
+                ->strftime("%Y %B"), 
+                 "\n";
+        }
+        # printf("%4d %2d\n", $i, $j) if isFridayStart($i, $j);
+    }
+}
+
diff --git a/challenge-038/cheok-yin-fung/README.md b/challenge-038/cheok-yin-fung/README.md
new file mode 100644
index 0000000000..743a767c7d
--- /dev/null
+++ b/challenge-038/cheok-yin-fung/README.md
@@ -0,0 +1,6 @@
+Goals:
+  
+- Java: Get familiar with the Date and Time API, 
+- Perl: Get familiar with Time::Piece (and Time::Seconds) module, especially the strftime and strptime methods
+
+attempt on 9th May, 2021
diff --git a/challenge-038/cheok-yin-fung/java/DateFinder.java b/challenge-038/cheok-yin-fung/java/DateFinder.java
new file mode 100644
index 0000000000..5945b73f53
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+++ b/challenge-038/cheok-yin-fung/java/DateFinder.java
@@ -0,0 +1,65 @@
+// The Weekly Challenge - 038 
+// Task 1 Date Finder
+// attempt: May 09th, 2021
+// from: C.-Y. Fung
+// Usage: java DateFinder [7-digit string]
+
+import java.time.LocalDate;
+import java.time.YearMonth;
+
+public class DateFinder
+{
+    public static void main(String[] args) 
+    {
+        String myYear = "", in_str = "";
+        try {
+            in_str = args[0];
+            for (char numChar : in_str.toCharArray()) {
+                if (numChar < '0' || numChar> '9') {
+                    System.out.println("Non-numeric character found.");
+                    throw new IllegalArgumentException();
+                }
+            }
+            switch(in_str.charAt(0)) {
+                case '1': myYear = "20"+in_str.substring(1,3); break;
+                case '2': myYear = "19"+in_str.substring(1,3); break;
+                default: throw new IllegalArgumentException();
+            }
+            if (in_str.length() != 7) { 
+                System.out.println("Input digits is not equal to 7.");
+                throw new IllegalArgumentException();
+            }
+        } catch (IllegalArgumentException e) {
+            System.out.println("Ilegal argument.");
+            System.exit(0);
+        } catch (IndexOutOfBoundsException e) {
+            System.out.println("Usage: java DateFinder [7-digit string]");
+            System.exit(0);
+        }
+
+        String myMonth = in_str.substring(3,5);
+        int myMonth_i = Integer.parseInt(myMonth);
+        try {
+            if (myMonth_i > 12 || myMonth_i < 1) 
+                throw new IllegalArgumentException();
+        } catch (IllegalArgumentException e) {
+            System.out.println("Problem in Month (within 01-12) " + myMonth);
+            System.exit(0);
+        }
+        String myDay = in_str.substring(5,7);
+        int myDay_i = Integer.parseInt(myDay);
+        int myYear_i = Integer.parseInt(myYear);
+        try {
+            YearMonth temp = YearMonth.of(myYear_i, myMonth_i);
+            int daysInMonth = temp.lengthOfMonth();
+            if (myDay_i > daysInMonth || myDay_i < 1) 
+                throw new IllegalArgumentException();
+        } catch (IllegalArgumentException e) {
+            System.out.println("Problem in date (last two digits) " + myDay);
+            System.exit(0);
+        } finally {
+            System.out.println(myYear + "-" + myMonth + "-" + myDay);        
+        }
+    }
+
+}
diff --git a/challenge-038/cheok-yin-fung/perl/ch-1.pl b/challenge-038/cheok-yin-fung/perl/ch-1.pl
new file mode 100644
index 0000000000..88f5e781f0
--- /dev/null
+++ b/challenge-038/cheok-yin-fung/perl/ch-1.pl
@@ -0,0 +1,32 @@
+#!/usr/bin/perl
+# The Weekly Challenge - 038 
+# Task 1 Date Finder
+# attempt: May 09th, 2021
+# from: C.-Y. Fung
+# Usage: ch-1.pl [7-digit string]
+# Java correspondence: DateFinder.java
+use Time::Piece;
+use strict;
+use warnings;
+
+my $str = $ARGV[0] || die "A 7-digit string is expected.";
+die "Format Error: A 7-digit string is expected." if length $str != 7;
+
+$str =~ s/^1/20/;
+$str =~ s/^2/19/;
+die "Error: first digit must be 1 or 2! " if $str =~ /[^12]/;
+
+my $Y = substr($str, 0, 4);
+my $Month = substr($str, 4, 2);
+my $d = substr($str, 6, 2);
+
+die "Problem in month ($Month)! " 
+    if $Month > 12 || $Month < 1;
+my $check = Time::Piece->strptime(substr($str,0,6)."01" , "%Y%m%d"); 
+die "Problem in date (last two digits: $d)! " 
+    if $d > $check->month_last_day || $d < 1;
+
+my $t = Time::Piece->strptime($str, "%Y%m%d"); 
+
+
+print $t->strftime("%Y-%m-%d"), "\n";