feat: Initial version

errors.go

@@ -0,0 +1,10 @@
+package main
+
+import "errors"
+
+var (
+	ErrNotNumber        = errors.New("Data is not numeric")
+	ErrInvalidColumn    = errors.New("Invalid column number")
+	ErrNoFiles          = errors.New("No input files")
+	ErrInvalidOperation = errors.New("Invalid operation")
+)