02 ternary numbers

tdd_intro/homework/02_ternary_numbers/test.cpp

@@ -1,4 +1,5 @@
 #include <gtest/gtest.h>
+#include <math.h>
 
 /*
 Convert a ternary number, represented as a string (e.g. '102012'), to its decimal equivalent using first principles.
@@ -16,3 +17,58 @@ The last place in a ternary number is the 1's place. The second to last is the 3
 
 If your language provides a method in the standard library to perform the conversion, pretend it doesn't exist and implement it yourself.
 */
+
+const std::string g_ternary302 = "102012";
+const std::string g_ternary303 = "102020";
+const std::string g_ternary304 = "102021";
+const std::string g_ternary305 = "102022";
+
+
+const std::string g_ternary222 = "22020";
+const std::string g_ternary333 = "110100";
+const std::string g_ternary765 = "1001100";
+const std::string g_ternary345 = "110210";
+
+
+uint32_t convert(const std::string &number)
+{
+    if (number.empty())
+        return -1;
+
+    int result = 0;
+    int place = number.size();
+    for (const char& a: number)
+    {
+        result += (a - '0') * std::pow(3, --place);
+    }
+    return result;
+}
+
+TEST (ternary_numbers, check_302)
+{
+    EXPECT_EQ(302, convert(g_ternary302));
+}
+
+TEST (ternary_numbers, check_303)
+{
+    EXPECT_EQ(303, convert(g_ternary303));
+}
+
+TEST (ternary_numbers, check_304)
+{
+    EXPECT_EQ(304, convert(g_ternary304));
+}
+
+TEST (ternary_numbers, check_305)
+{
+    EXPECT_EQ(305, convert(g_ternary305));
+}
+
+TEST (ternary_numbers, acceptance)
+{
+    EXPECT_EQ(222, convert(g_ternary222));
+    EXPECT_EQ(333, convert(g_ternary333));
+    EXPECT_EQ(765, convert(g_ternary765));
+    EXPECT_EQ(345, convert(g_ternary345));
+    EXPECT_EQ(-1, convert(""));
+}