Add triangle exercise

config.json

@@ -170,6 +170,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "triangle",
+        "name": "Triangle",
+        "uuid": "30e46a93-4c84-4b5f-8006-ddde0f155b09",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 3
+      },
       {
         "slug": "atbash-cipher",
         "name": "Atbash Cipher",

exercises/practice/triangle/.docs/instructions.md

@@ -0,0 +1,29 @@
+# Instructions
+
+Determine if a triangle is equilateral, isosceles, or scalene.
+
+An _equilateral_ triangle has all three sides the same length.
+
+An _isosceles_ triangle has at least two sides the same length.
+(It is sometimes specified as having exactly two sides the same length, but for the purposes of this exercise we'll say at least two.)
+
+A _scalene_ triangle has all sides of different lengths.
+
+## Note
+
+For a shape to be a triangle at all, all sides have to be of length > 0, and the sum of the lengths of any two sides must be greater than or equal to the length of the third side.
+
+In equations:
+
+Let `a`, `b`, and `c` be sides of the triangle.
+Then all three of the following expressions must be true:
+
+```text
+a + b ≥ c
+b + c ≥ a
+a + c ≥ b
+```
+
+See [Triangle Inequality][triangle-inequality]
+
+[triangle-inequality]: https://en.wikipedia.org/wiki/Triangle_inequality

exercises/practice/triangle/.meta/config.json

@@ -0,0 +1,19 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "triangle.s"
+    ],
+    "test": [
+      "triangle_test.c"
+    ],
+    "example": [
+      ".meta/example.s"
+    ]
+  },
+  "blurb": "Determine if a triangle is equilateral, isosceles, or scalene.",
+  "source": "The Ruby Koans triangle project, parts 1 & 2",
+  "source_url": "https://web.archive.org/web/20220831105330/http://rubykoans.com"
+}

exercises/practice/triangle/.meta/example.s

@@ -0,0 +1,65 @@
+.text
+.globl equilateral
+.globl isosceles
+.globl scalene
+
+/* extern int equilateral(int a, int b, int c); */
+equilateral:
+        cbz     x0, reject
+
+        cmp     x0, x1
+        bne     reject
+
+        cmp     x0, x2
+        bne     reject
+
+accept:
+        mov     x0, #1
+        ret
+
+/* extern int isosceles(int a, int b, int c); */
+isosceles:
+        cmp     x0, x1
+        beq     triangle
+
+        cmp     x0, x2
+        beq     triangle
+
+        cmp     x1, x2
+        beq     triangle
+
+reject:
+        mov     x0, xzr
+        ret
+
+/* extern int scalene(int a, int b, int c); */
+scalene:
+        cmp     x0, x1
+        beq     reject
+
+        cmp     x0, x2
+        beq     reject
+
+        cmp     x1, x2
+        beq     reject
+
+triangle:
+        cbz     x0, reject
+
+        cbz     x1, reject
+
+        cbz     x2, reject
+
+        add     x3, x1, x2
+        cmp     x0, x3
+        bgt     reject
+
+        add     x3, x0, x2
+        cmp     x1, x3
+        bgt     reject
+
+        add     x3, x0, x1
+        cmp     x2, x3
+        bgt     reject
+
+        b       accept

exercises/practice/triangle/.meta/tests.toml

@@ -0,0 +1,76 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[8b2c43ac-7257-43f9-b552-7631a91988af]
+description = "equilateral triangle -> all sides are equal"
+
+[33eb6f87-0498-4ccf-9573-7f8c3ce92b7b]
+description = "equilateral triangle -> any side is unequal"
+
+[c6585b7d-a8c0-4ad8-8a34-e21d36f7ad87]
+description = "equilateral triangle -> no sides are equal"
+
+[16e8ceb0-eadb-46d1-b892-c50327479251]
+description = "equilateral triangle -> all zero sides is not a triangle"
+
+[3022f537-b8e5-4cc1-8f12-fd775827a00c]
+description = "equilateral triangle -> sides may be floats"
+include = false
+
+[cbc612dc-d75a-4c1c-87fc-e2d5edd70b71]
+description = "isosceles triangle -> last two sides are equal"
+
+[e388ce93-f25e-4daf-b977-4b7ede992217]
+description = "isosceles triangle -> first two sides are equal"
+
+[d2080b79-4523-4c3f-9d42-2da6e81ab30f]
+description = "isosceles triangle -> first and last sides are equal"
+
+[8d71e185-2bd7-4841-b7e1-71689a5491d8]
+description = "isosceles triangle -> equilateral triangles are also isosceles"
+
+[840ed5f8-366f-43c5-ac69-8f05e6f10bbb]
+description = "isosceles triangle -> no sides are equal"
+
+[2eba0cfb-6c65-4c40-8146-30b608905eae]
+description = "isosceles triangle -> first triangle inequality violation"
+
+[278469cb-ac6b-41f0-81d4-66d9b828f8ac]
+description = "isosceles triangle -> second triangle inequality violation"
+
+[90efb0c7-72bb-4514-b320-3a3892e278ff]
+description = "isosceles triangle -> third triangle inequality violation"
+
+[adb4ee20-532f-43dc-8d31-e9271b7ef2bc]
+description = "isosceles triangle -> sides may be floats"
+include = false
+
+[e8b5f09c-ec2e-47c1-abec-f35095733afb]
+description = "scalene triangle -> no sides are equal"
+
+[2510001f-b44d-4d18-9872-2303e7977dc1]
+description = "scalene triangle -> all sides are equal"
+
+[c6e15a92-90d9-4fb3-90a2-eef64f8d3e1e]
+description = "scalene triangle -> first and second sides are equal"
+
+[3da23a91-a166-419a-9abf-baf4868fd985]
+description = "scalene triangle -> first and third sides are equal"
+
+[b6a75d98-1fef-4c42-8e9a-9db854ba0a4d]
+description = "scalene triangle -> second and third sides are equal"
+
+[70ad5154-0033-48b7-af2c-b8d739cd9fdc]
+description = "scalene triangle -> may not violate triangle inequality"
+
+[26d9d59d-f8f1-40d3-ad58-ae4d54123d7d]
+description = "scalene triangle -> sides may be floats"
+include = false

exercises/practice/triangle/Makefile

@@ -0,0 +1,36 @@
+AS = aarch64-linux-gnu-as
+CC = aarch64-linux-gnu-gcc
+
+CFLAGS = -g -Wall -Wextra -pedantic -Werror
+LDFLAGS =
+
+ALL_LDFLAGS = -pie -Wl,--fatal-warnings
+
+ALL_CFLAGS = -std=c99 -fPIE $(CFLAGS)
+ALL_LDFLAGS += $(LDFLAGS)
+
+C_OBJS = $(patsubst %.c,%.o,$(wildcard *.c))
+AS_OBJS = $(patsubst %.s,%.o,$(wildcard *.s))
+ALL_OBJS = $(filter-out example.o,$(C_OBJS) $(AS_OBJS) vendor/unity.o)
+
+CC_CMD = $(CC) $(ALL_CFLAGS) -c -o $@ $<
+
+all: tests
+	qemu-aarch64 -L /usr/aarch64-linux-gnu ./$<
+
+tests: $(ALL_OBJS)
+	@$(CC) $(ALL_CFLAGS) $(ALL_LDFLAGS) -o $@ $(ALL_OBJS)
+
+%.o: %.s
+	@$(AS) -o $@ $<
+
+%.o: %.c
+	@$(CC_CMD)
+
+vendor/unity.o: vendor/unity.c vendor/unity.h vendor/unity_internals.h
+	@$(CC_CMD)
+
+clean:
+	@rm -f *.o vendor/*.o tests
+
+.PHONY: all clean

exercises/practice/triangle/triangle.s

@@ -0,0 +1,13 @@
+.text
+.globl equilateral
+.globl isosceles
+.globl scalene
+
+equilateral:
+    ret
+
+isosceles:
+    ret
+
+scalene:
+    ret

exercises/practice/triangle/triangle_test.c

@@ -0,0 +1,123 @@
+#include "vendor/unity.h"
+
+extern int equilateral(int a, int b, int c);
+extern int isosceles(int a, int b, int c);
+extern int scalene(int a, int b, int c);
+
+void setUp(void) {
+}
+
+void tearDown(void) {
+}
+
+void test_equilateral_all_sides_are_equal(void) {
+    TEST_ASSERT_TRUE(equilateral(2, 2, 2));
+}
+
+void test_equilateral_any_side_is_unequal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(equilateral(2, 3, 2));
+}
+
+void test_equilateral_no_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(equilateral(5, 4, 6));
+}
+
+void test_equilateral_all_zero_sides_is_not_a_triangle(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(equilateral(0, 0, 0));
+}
+
+void test_isosceles_last_two_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(isosceles(3, 4, 4));
+}
+
+void test_isosceles_first_two_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(isosceles(4, 4, 3));
+}
+
+void test_isosceles_first_and_last_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(isosceles(4, 3, 4));
+}
+
+void test_isosceles_equilateral_triangles_are_also_isosceles(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(isosceles(4, 4, 4));
+}
+
+void test_isosceles_no_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(isosceles(2, 3, 4));
+}
+
+void test_isosceles_first_triangle_inequality_violation(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(isosceles(1, 1, 3));
+}
+
+void test_isosceles_second_triangle_inequality_violation(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(isosceles(1, 3, 1));
+}
+
+void test_isosceles_third_triangle_inequality_violation(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(isosceles(3, 1, 1));
+}
+
+void test_scalene_no_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_TRUE(scalene(5, 4, 6));
+}
+
+void test_scalene_all_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(scalene(4, 4, 4));
+}
+
+void test_scalene_first_and_second_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(scalene(4, 4, 3));
+}
+
+void test_scalene_first_and_third_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(scalene(3, 4, 3));
+}
+
+void test_scalene_second_and_third_sides_are_equal(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(scalene(4, 3, 3));
+}
+
+void test_scalene_may_not_violate_triangle_inequality(void) {
+    TEST_IGNORE();
+    TEST_ASSERT_FALSE(scalene(7, 3, 2));
+}
+
+int main(void) {
+    UNITY_BEGIN();
+    RUN_TEST(test_equilateral_all_sides_are_equal);
+    RUN_TEST(test_equilateral_any_side_is_unequal);
+    RUN_TEST(test_equilateral_no_sides_are_equal);
+    RUN_TEST(test_equilateral_all_zero_sides_is_not_a_triangle);
+    RUN_TEST(test_isosceles_last_two_sides_are_equal);
+    RUN_TEST(test_isosceles_first_two_sides_are_equal);
+    RUN_TEST(test_isosceles_first_and_last_sides_are_equal);
+    RUN_TEST(test_isosceles_equilateral_triangles_are_also_isosceles);
+    RUN_TEST(test_isosceles_no_sides_are_equal);
+    RUN_TEST(test_isosceles_first_triangle_inequality_violation);
+    RUN_TEST(test_isosceles_second_triangle_inequality_violation);
+    RUN_TEST(test_isosceles_third_triangle_inequality_violation);
+    RUN_TEST(test_scalene_no_sides_are_equal);
+    RUN_TEST(test_scalene_all_sides_are_equal);
+    RUN_TEST(test_scalene_first_and_second_sides_are_equal);
+    RUN_TEST(test_scalene_first_and_third_sides_are_equal);
+    RUN_TEST(test_scalene_second_and_third_sides_are_equal);
+    RUN_TEST(test_scalene_may_not_violate_triangle_inequality);
+    return UNITY_END();
+}