2 ternary numbers

.gitignore

@@ -30,3 +30,9 @@
 *.exe
 *.out
 *.app
+
+# Build dirs
+build-*
+
+# .user files
+*.user

tdd_intro/homework/02_ternary_numbers/test.cpp

@@ -16,3 +16,67 @@ 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.
 */
+
+int CharToInt(char c)
+{
+    return c - '0';
+}
+
+int Power(int number, int index)
+{
+    int result = 1;
+    for (int i = 0; i < index; i++)
+    {
+        result *= number;
+    }
+    return result;
+}
+std::vector<int> ParseDigits(const std::string& number)
+{
+    std::vector<int> result;
+    for (char ch : number)
+    {
+        result.push_back(CharToInt(ch));
+    }
+    return result;
+}
+int TerToDec(const std::string& ternary)
+{
+    int result = 0;
+    std::vector<int> digits = ParseDigits(ternary);
+    size_t i = 0;
+    for (auto digit = digits.rbegin(); digit != digits.rend(); ++digit)
+    {
+        result += *digit * Power(3, i);
+        i++;
+    }
+    return result;
+}
+
+TEST(PowerTest, ItReturnsNumberMultipliedByNumberNTimesForIndexN)
+{
+    EXPECT_EQ(5, Power(5, 1));
+    EXPECT_EQ(25, Power(5, 2));
+    EXPECT_EQ(625, Power(5, 4));
+}
+TEST(ParseDigitsTest, ItReturnsVectorWithDigitsForMultipleDigits)
+{
+    EXPECT_EQ(std::vector<int>({ 1 }), ParseDigits("1"));
+    EXPECT_EQ(std::vector<int>({ 1, 2, 3 }), ParseDigits("123"));
+    EXPECT_EQ(std::vector<int>({ 1, 2, 3, 1 }), ParseDigits("1231"));
+}
+
+TEST(TerToDecTest, ItReturnsZeroForZero)
+{
+    EXPECT_EQ(0, TerToDec("0"));
+}
+TEST(TerToDecTest, ItReturnsDecRepresentationForAnyNumber)
+{
+    EXPECT_EQ(1, TerToDec("1"));
+    EXPECT_EQ(4, TerToDec("11"));
+    EXPECT_EQ(13, TerToDec("111"));
+}
+TEST(TerToDecTest, Acceptance)
+{
+    EXPECT_EQ(302, TerToDec("102012"));
+}