Rust - Solved Difference of Squares

rust/difference-of-squares/.gitignore

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+# Generated by Cargo
+# will have compiled files and executables
+/target/
+
+# Remove Cargo.lock from gitignore if creating an executable, leave it for libraries
+# More information here http://doc.crates.io/guide.html#cargotoml-vs-cargolock
+Cargo.lock

rust/difference-of-squares/Cargo.toml

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+[package]
+name = "difference-of-squares"
+version = "0.0.0"

rust/difference-of-squares/README.md

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+# Difference Of Squares
+
+Find the difference between the square of the sum and the sum of the squares of the first N natural numbers.
+
+The square of the sum of the first ten natural numbers is
+(1 + 2 + ... + 10)² = 55² = 3025.
+
+The sum of the squares of the first ten natural numbers is
+1² + 2² + ... + 10² = 385.
+
+Hence the difference between the square of the sum of the first
+ten natural numbers and the sum of the squares of the first ten
+natural numbers is 3025 - 385 = 2640.
+
+## Rust Installation
+
+Refer to the [exercism help page][help-page] for Rust installation and learning
+resources.
+
+## Writing the Code
+
+Execute the tests with:
+
+```bash
+$ cargo test
+```
+
+All but the first test have been ignored.  After you get the first test to
+pass, remove the ignore flag (`#[ignore]`) from the next test and get the tests
+to pass again.  The test file is located in the `tests` directory.   You can
+also remove the ignore flag from all the tests to get them to run all at once
+if you wish.
+
+Make sure to read the [Crates and Modules](https://doc.rust-lang.org/stable/book/crates-and-modules.html) chapter if you
+haven't already, it will help you with organizing your files.
+
+## Feedback, Issues, Pull Requests
+
+The [exercism/xrust](https://github.com/exercism/xrust) repository on GitHub is the home for all of the Rust exercises. If you have feedback about an exercise, or want to help implement new exercises, head over there and create an issue. Members of the [rust track team](https://github.com/orgs/exercism/teams/rust) are happy to help!
+
+If you want to know more about Exercism, take a look at the [contribution guide](https://github.com/exercism/x-common/blob/master/CONTRIBUTING.md).
+
+[help-page]: http://exercism.io/languages/rust
+[crates-and-modules]: http://doc.rust-lang.org/stable/book/crates-and-modules.html
+
+## Source
+
+Problem 6 at Project Euler [http://projecteuler.net/problem=6](http://projecteuler.net/problem=6)
+
+## Submitting Incomplete Problems
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.
+

rust/difference-of-squares/src/lib.rs

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+pub fn sum_of_squares(x: i64) -> i64 {
+    let mut y: i64 = 0;
+    for i in (1..(x + 1)){
+        y += i.pow(2);
+    }
+    return y;
+}
+
+pub fn square_of_sum(x: i64) -> i64 {
+    let mut y: i64 = 0;
+    for i in (1..(x + 1)){
+        y += i;
+    }
+    y = y.pow(2);
+    return y;
+}
+
+pub fn difference(x: i64) -> i64 {
+    return square_of_sum(x) - sum_of_squares(x);
+}

rust/difference-of-squares/tests/difference-of-square.rs

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+extern crate difference_of_squares as squares;
+
+#[test]
+fn test_square_of_sum_5() {
+    assert_eq!(225, squares::square_of_sum(5));
+}
+
+#[test]
+fn test_sum_of_squares_5() {
+    assert_eq!(55, squares::sum_of_squares(5));
+}
+
+#[test]
+fn test_difference_5() {
+    assert_eq!(170, squares::difference(5));
+}
+
+#[test]
+fn test_square_of_sum_100() {
+    assert_eq!(25502500, squares::square_of_sum(100));
+}
+
+#[test]
+fn test_sum_of_squares_100() {
+    assert_eq!(338350, squares::sum_of_squares(100));
+}
+
+#[test]
+fn test_difference_100() {
+    assert_eq!(25164150, squares::difference(100));
+}