INIT: task4

files/hw1.txt

@@ -21,3 +21,9 @@
 ./hw1/task3/Cargo.toml
 ./hw1/task3/src/lib.rs
 ./hw1/task3/tests/task3.rs
+
+
+./hw1/task4/Cargo.toml
+./hw1/task4/src/lib.rs
+./hw1/task4/tests/task4.rs
+

hw1/task4/README.md

@@ -0,0 +1,22 @@
+# Homework hw1 task 4
+
+## prepare your task
+
+Run `cargo init` in your `task4/` directory.
+
+## task
+
+Find the difference between the sum of the squares and the square of the sum of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is,
+
+    (1 + 2 + ... + 10)**2 = 55**2 = 3025
+
+The sum of the squares of the first ten natural numbers is,
+
+    1**2 + 2**2 + ... + 10**2 = 385
+
+Hence the difference between the square of the sum of the first
+ten natural numbers and the sum of the squares is 2640:
+
+    3025 - 385 = 2640

hw1/task4/src/lib.rs

@@ -0,0 +1,11 @@
+pub fn square_of_sum(n: i32) -> i32 {
+    unimplemented!();
+}
+
+pub fn sum_of_squares(n: i32) -> i32 {
+    unimplemented!();
+}
+
+pub fn difference(n: i32) -> i32 {
+    unimplemented!();
+}

hw1/task4/tests/task4.rs

@@ -0,0 +1,31 @@
+extern crate task4;
+
+#[test]
+fn test_square_of_sum_5() {
+    assert_eq!(225, task4::square_of_sum(5));
+}
+
+#[test]
+fn test_sum_of_squares_5() {
+    assert_eq!(55, task4::sum_of_squares(5));
+}
+
+#[test]
+fn test_difference_5() {
+    assert_eq!(170, task4::difference(5));
+}
+
+#[test]
+fn test_square_of_sum_100() {
+    assert_eq!(25502500, task4::square_of_sum(100));
+}
+
+#[test]
+fn test_sum_of_squares_100() {
+    assert_eq!(338350, task4::sum_of_squares(100));
+}
+
+#[test]
+fn test_difference_100() {
+    assert_eq!(25164150, task4::difference(100));
+}