019 ok

019/Cargo.toml

@@ -0,0 +1,10 @@
+[package]
+name = "peulerproblem"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+time = "0.3.20"
+

019/src/main.rs

@@ -0,0 +1,25 @@
+use time::Date;
+use time::Month;
+use time::Duration;
+
+fn main() {
+    let d_begin = Date::from_calendar_date(1901, Month::January, 1).unwrap();
+    let d_end = Date::from_calendar_date(2000, Month::December, 31).unwrap();
+    let dt = Duration::DAY;
+    let mut day_count = 0u32;
+    let mut sundays_count = 0u32;
+    let mut di = d_begin.clone();
+    while di != d_end {
+        if di.weekday() == time::Weekday::Sunday {
+            if di.day() == 1 {
+                sundays_count += 1;
+            }
+        }
+        //println!("{}", di.weekday());
+        di = di.checked_add(dt).unwrap();
+        day_count += 1;
+    }
+
+    println!("day_count: {}", day_count);
+    println!("sundays count: {}", sundays_count);
+}