Code Smell 219 - Looping from index 0
Counting from zero seems natural. Doesn't it?
I’m a senior software engineer loving clean code, and declarative designs. S.O.L.I.D. and agile methodologies fan.
TL;DR: Start counting from one instead of zero. Like humans do.
Problems
Bijection from real-world broken
Cognitive load
Overly implementation-oriented code
Solutions
- Favor high-level declarative languages
Context
Low-level languages force you to think at a machine level.
Hardware turning machines were designed to use binary gates and start indexing at 0.
A few programming languages use one-based indexing, where indexing starts from 1.
These languages are known for being higher level and more declarative:
Basic / Visual Basic
Pascal
Smalltalk
Fortran
Lua
MATLAB
R
Julia
Sample Code
Wrong
package main
import "fmt"
func main() {
numbers := []int{10, 20, 30, 40, 50}
for i := 0; i < len(numbers); i++ {
// Iteration goes from zero to len-1
fmt.Println(numbers[i])
}
}
Right
numbers = [10, 20, 30, 40, 50];
% Looping through the array using one-based indexing
% from 1 to length
for currentIndex = 1:length(numbers)
disp(numbers(currentIndex));
end
Detection
[X] Automatic
This is a language smell.
Exceptions
- Low-level optimized code
Tags
- Declarative Code
Conclusion
We need to think as humans when we code and not as machines.
Humans count from one.
Zero number was a brilliant discovery in math and science but it does not apply to everyday counting.
Relations
More Info
Disclaimer
Code Smells are my opinion.
Credits
Photo by Andy Kelly on Unsplash
Pay attention to zeros. If there is a zero, someone will divide by it.
Cem Kaner
This article is part of the CodeSmell Series.
My new book about clean code is available for pre-order.
You will find several recipes like this one with a higher level of detail
