Now build the -n flag of the cat tool, as a new function. It prints every line preceded by its 1-based line number, right-aligned in 6 columns, then a tab character, then the line text. Blank lines are numbered too, and an empty list gives an empty string.
Function signature:
func numberedCat(lines []string) string
Format per line: the line number right-aligned in a field 6 characters wide (padded with spaces on the left), then a literal tab (\t), then the original line.
Example:
Input: lines = ["hello", "world", "foo"]
Output:
" 1\thello\n 2\tworld\n 3\tfoo"
When printed:
1 hello
2 world
3 foo
Build the result manually: walk through the lines by index and accumulate them into a single
string, putting a "\n" before every line except the first.
fmt.Sprintf("%6d\t%s", i+1, lines[i]) formats one entry; %6d right-aligns the integer in 6 columns.
The full solution:
func numberedCat(lines []string) string {
result := ""
for i := 0; i < len(lines); i++ {
if i > 0 {
result += "\n"
}
result += fmt.Sprintf("%6d\t%s", i+1, lines[i])
}
return result
}
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