Add C solution

3 files changed, 90 insertions, 4 deletions

diff --git a/challenge-132/paulo-custodio/Makefile b/challenge-132/paulo-custodio/Makefile
new file mode 100644
index 0000000000..c3c762d746
--- /dev/null
+++ b/challenge-132/paulo-custodio/Makefile
@@ -0,0 +1,2 @@
+all:
+	perl ../../challenge-001/paulo-custodio/test.pl
diff --git a/challenge-132/paulo-custodio/c/ch-1.c b/challenge-132/paulo-custodio/c/ch-1.c
new file mode 100644
index 0000000000..91d89db0ed
--- /dev/null
+++ b/challenge-132/paulo-custodio/c/ch-1.c
@@ -0,0 +1,88 @@
+/*
+Challenge 132
+
+TASK #1 > Mirror Dates
+Submitted by: Mark Anderson
+You are given a date (yyyy/mm/dd).
+
+Assuming, the given date is your date of birth. Write a script to find the
+mirror dates of the given date.
+
+Dave Cross has built cool site that does something similar.
+
+Assuming today is 2021/09/22.
+Example 1:
+Input: 2021/09/18
+Output: 2021/09/14, 2021/09/26
+
+On the date you were born, someone who was your current age, would have
+been born on 2021/09/14.
+Someone born today will be your current age on 2021/09/26.
+Example 2:
+Input: 1975/10/10
+Output: 1929/10/27, 2067/09/05
+
+On the date you were born, someone who was your current age, would have
+been born on 1929/10/27.
+Someone born today will be your current age on 2067/09/05.
+Example 3:
+Input: 1967/02/14
+Output: 1912/07/08, 2076/04/30
+
+On the date you were born, someone who was your current age, would have
+been born on 1912/07/08.
+Someone born today will be your current age on 2076/04/30.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+
+// https://pdc.ro.nu/jd-code.html
+long gregorian_date_to_jd(int y, int m, int d) {
+    y += 8000;
+    if (m < 3) { y--; m += 12; }
+    return (y * 365) + (y / 4) - (y / 100) + (y / 400) - 1200820
+        + (m * 153 + 3) / 5 - 92 + d - 1;
+}
+
+void jd_to_gregorian_date(long jd, int* yp, int* mp, int* dp) {
+    int y, m, d;
+    for (y = jd / 366 - 4715; gregorian_date_to_jd(y + 1, 1, 1) <= jd; y++);
+    for (m = 1; gregorian_date_to_jd(y, m + 1, 1) <= jd; m++);
+    for (d = 1; gregorian_date_to_jd(y, m, d + 1) <= jd; d++);
+    *yp = y; *mp = m; *dp = d;
+}
+
+
+int main(int argc, char* argv[]) {
+    if (argc != 3) {
+        fputs("usage: ch-1 birth_date today", stderr);
+        return EXIT_FAILURE;
+    }
+
+    int by, bm, bd;
+    if (sscanf(argv[1], "%d/%d/%d", &by, &bm, &bd) != 3) {
+        fputs("invalid birth date", stderr);
+        return EXIT_FAILURE;
+    }
+
+    int ty, tm, td;
+    if (sscanf(argv[2], "%d/%d/%d", &ty, &tm, &td) != 3) {
+        fputs("invalid birth date", stderr);
+        return EXIT_FAILURE;
+    }
+
+    long bjd = gregorian_date_to_jd(by, bm, bd);
+    long tjd = gregorian_date_to_jd(ty, tm, td);
+    long days = tjd - bjd;
+    long mirror1_jd = bjd - days;
+    long mirror2_jd = tjd + days;
+
+    int m1y, m1m, m1d;
+    jd_to_gregorian_date(mirror1_jd, &m1y, &m1m, &m1d);
+
+    int m2y, m2m, m2d;
+    jd_to_gregorian_date(mirror2_jd, &m2y, &m2m, &m2d);
+
+    printf("%04d/%02d/%02d, %04d/%02d/%02d\n", m1y, m1m, m1d, m2y, m2m, m2d);
+}
diff --git a/challenge-132/paulo-custodio/test.pl b/challenge-132/paulo-custodio/test.pl
deleted file mode 100644
index ba6c37260b..0000000000
--- a/challenge-132/paulo-custodio/test.pl
+++ /dev/null
@@ -1,4 +0,0 @@
-#!/usr/bin/env perl
-use Modern::Perl;
-use Test::More;
-require '../../challenge-001/paulo-custodio/test.pl';