C code for challenge 1

1 files changed, 37 insertions, 0 deletions

diff --git a/challenge-326/walt-mankowski/c/ch-1.c b/challenge-326/walt-mankowski/c/ch-1.c
new file mode 100644
index 0000000000..f325530a39
--- /dev/null
+++ b/challenge-326/walt-mankowski/c/ch-1.c
@@ -0,0 +1,37 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <string.h>
+
+void usage() {
+    printf("Usage: ch-1 YYYY-MM-DD\n");
+    exit(1);
+}
+
+int main(int argc, char *argv[]) {
+    struct tm tm;
+    if (argc != 2)
+        usage();
+
+    /* Make a copy of argv[1] so we can call strtok() on it */
+    char *yyyymmdd = malloc(strlen(argv[1]) + 1);
+    strcpy(yyyymmdd, argv[1]);
+
+    /* parse the date */
+    int year = atoi(strtok(yyyymmdd, "-"));
+    int month = atoi(strtok(NULL, "-"));
+    int mday = atoi(strtok(NULL, "-"));
+
+    /* construct a struct tm with the year, month, and day */
+    memset(&tm, 0, sizeof(tm));
+    tm.tm_year = year - 1900;
+    tm.tm_mon = month - 1;
+    tm.tm_mday = mday;
+
+    /* get the epoch time for midnight on that date */
+    time_t t = mktime(&tm);
+
+    /* get the yday for that date */
+    struct tm *new_tm = gmtime(&t);
+    printf("%d\n", new_tm->tm_yday + 1);
+}