Add a solution for lcd

lcd/solution/lcd.cpp

@@ -0,0 +1,68 @@
+#include "lcd.hpp"
+
+lcd_grid lcd(const std::string & s1,
+             const std::string & s2,
+             const std::string & s3) {
+  lcd_grid result;
+  result.push_back(s1);
+  result.push_back(s2);
+  result.push_back(s3);
+  return result;
+}
+
+const lcd_grid digits[] =
+    {
+        lcd(" _ ",
+            "| |",
+            "|_|"
+        ),
+        lcd("   ",
+            "  |",
+            "  |"
+        ),
+        lcd(" _ ",
+            " _|",
+            "|_ "
+        ),
+        lcd(" _ ",
+            " _|",
+            " _|"
+        ),
+        lcd("   ",
+            "|_|",
+            "  |"
+        ),
+        lcd(" _ ",
+            "|_ ",
+            " _|"
+        ),
+        lcd(" _ ",
+            "|_ ",
+            "|_|"
+        ),
+        lcd(" _ ",
+            "  |",
+            "  |"
+        ),
+        lcd(" _ ",
+            "|_|",
+            "|_|"
+        ),
+        lcd(" _ ",
+            "|_|",
+            "  |"
+        ),
+    };
+
+lcd_grid lcd(int value) {
+  if (value < 10)
+    return digits[value];
+  else {
+    lcd_grid lhs = lcd(value / 10);
+    lcd_grid rhs = digits[value % 10];
+    return lcd(
+        lhs[0] + ' ' + rhs[0],
+        lhs[1] + ' ' + rhs[1],
+        lhs[2] + ' ' + rhs[2]);
+  }
+}

lcd/solution/lcd_tests.cpp

@@ -0,0 +1,110 @@
+#include <gtest/gtest.h>
+
+#include "lcd.hpp"
+#include <iostream>
+
+std::string to_string(const lcd_grid & grid) {
+  std::stringstream output;
+  for (const auto & str: grid)
+    output << str;
+  return output.str();
+}
+
+void lcd_spec(int value, const lcd_grid & grid) {
+  std::string expected = to_string(grid),
+      actual = to_string(lcd(value));
+  if (expected != actual) {
+    std::cerr
+        << "lcd(" << value << ")\n"
+        << "expected==\n"
+        << expected << '\n'
+        << "actual==\n"
+        << actual << std::endl;
+    std::exit(EXIT_FAILURE);
+  }
+}
+
+TEST(LcdTest, Zero) {
+  lcd_spec(0, lcd(
+      " _ ",
+      "| |",
+      "|_|"
+  ));
+}
+
+TEST(LcdTest, One) {
+  lcd_spec(1, lcd(
+      "   ",
+      "  |",
+      "  |"
+  ));
+}
+
+TEST(LcdTest, Two) {
+  lcd_spec(2, lcd(
+      " _ ",
+      " _|",
+      "|_ "
+  ));
+}
+
+TEST(LcdTest, Three) {
+  lcd_spec(3, lcd(
+      " _ ",
+      " _|",
+      " _|"
+  ));
+}
+
+TEST(LcdTest, Four) {
+  lcd_spec(4, lcd(
+      "   ",
+      "|_|",
+      "  |"
+  ));
+}
+
+TEST(LcdTest, Twelve) {
+  lcd_spec(12, lcd(
+      "     _ ",
+      "  |  _|",
+      "  | |_ "
+  ));
+}
+
+TEST(LcdTest, TwentyFive) {
+  lcd_spec(25, lcd(
+      " _   _ ",
+      " _| |_ ",
+      "|_   _|"
+  ));
+}
+
+TEST(LcdTest, SixtyFour) {
+  lcd_spec(64, lcd(
+      " _     ",
+      "|_  |_|",
+      "|_|   |"
+  ));
+}
+
+TEST(LcdTest, SeventyFour) {
+  lcd_spec(74, lcd(
+      " _     ",
+      "  | |_|",
+      "  |   |"
+  ));
+}
+
+TEST(LcdTest, EightyNine) {
+  lcd_spec(89, lcd(
+      " _   _ ",
+      "|_| |_|",
+      "|_|   |"
+  ));
+}
+
+int main(int argc, char * argv[]) {
+  testing::InitGoogleTest(&argc, argv);
+  return RUN_ALL_TESTS();
+}

lcd/solution/main.cpp

@@ -0,0 +1,12 @@
+#include <iostream>
+#include "lcd.hpp"
+
+static const int MAX = 100;
+
+int main() {
+  for (int i = 0; i < MAX; i++) {
+    auto grid = lcd(i);
+    for (const auto & line: grid)
+      std::cout << line << "\n";
+  }
+}