Added #19 Counting Sundays

2 files changed, 29 insertions, 0 deletions

diff --git a/19-Counting-Sundays/countsundays b/19-Counting-Sundays/countsundays
new file mode 100755
index 0000000..f5f9aa9
--- /dev/null
+++ b/19-Counting-Sundays/countsundays
diff --git a/19-Counting-Sundays/countsundays.c b/19-Counting-Sundays/countsundays.c
new file mode 100644
index 0000000..e3f4d5a
--- /dev/null
+++ b/19-Counting-Sundays/countsundays.c
@@ -0,0 +1,29 @@
+#include <stdio.h>
+#include <time.h>
+
+// Implemented a timing routine for fun :)
+
+int main(){
+    clock_t now, then;
+    int c = 0;
+    struct tm time = {0};
+
+    then = clock();
+    time.tm_mday = 1;
+
+    // Starting from 1-1-1901
+    for(int y = 1; y <= 100; y++){
+	for(int m = 0; m < 12; m++){ // Apparently January is the 0th month, 
+            time.tm_mon = m;        // even though there's no 0th day.... wtf K&R??
+	    time.tm_year = y;
+	    time_t inttime = mktime(&time);
+	    struct tm *t = localtime(&inttime);
+	    if(t->tm_wday == 0)
+		c++;
+	}
+    }
+    printf("%d\n", c);
+    now = clock();
+    printf("Only took %f ms\n", (double)(now - then) / (CLOCKS_PER_SEC / 1000));
+    return 0;
+}