Learn to Code In 5 Minutes A Day: Lesson 12

Lesson 11 Solution

Yesterday you were supposed to add a unit test and code for the roman numeral 5.

Did you come up with this?

Unit Test:

func TestRoman5(t *testing.T) {
	result := roman(5)
	expected := "V"
	if result != expected {
		t.Errorf("result was incorrect, got: %v, want: %v.", result, expected)
	}
}

Run the Test

Did you remember to run the test first before trying to solve it?

go test   
--- FAIL: TestRoman5 (0.00s)
    roman_test.go:39: result was incorrect, got: IIIII, want: V.
FAIL
exit status 1
FAIL    hello   0.394s

Solve the Test

func roman(number int) string {
	result := ""
	if number == 5 {
		result = "V"
		number = number - 5
	}
	if number == 4 {
		result = "IV"
		number = number - 4
	}
	for i := 0; i < number; i++ {
		result += "I"
	}
	return result
}

Test the Solution

% go test
PASS
ok      hello   0.205s

Assignment 12: Roman Numerals 6, 7, 8

Can you figure out how to solve Roman Numerals 6, 7, and 8?

Here are some hints for how to do it correctly:

1. Write the unit test for 6. Then run it. Look at the output.
2. Can you figure out how to change one of the comparison operators in the solution to make 6 work?
3. Does making 6 work also solve for other numbers? Can you prove it by writing those tests?

• learn to code
• lesson 12
• golang