Longest Word in Go

Published on 19 March 2023 (Updated: 19 March 2023)

Welcome to the Longest Word in Go page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

package main

import (

const errorMessage = "Usage: please provide a string"

// longestWordLength returns the length of the longest word
// in a string. The words in the string should be separated
// by spaces, tabs, newlines, and/or carriage returns.
func longestWordLength(str string) int {
    words := strings.FieldsFunc(str, isLimitedWhitespace)
    return longestStringLength(words)

// isLimitedWhitespace returns whether a rune is one of four
// whitespace runes: ' ', '\t', '\n', '\r'
// Note that this is NOT equivalent to unicode.IsSpace which
// includes addtional whitespace runes
func isLimitedWhitespace(r rune) bool {
    return strings.ContainsRune(" \t\n\r", r)

// longestStringLength returns the length of the longest string
// in the slice
func longestStringLength(strs []string) (longest int) {
    for _, str := range strs {
        if len(str) > longest {
            longest = len(str)

func main() {
    if len(os.Args) < 2 || len(os.Args[1]) == 0 {
    } else {

Longest Word in Go was written by:

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How to Implement the Solution

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How to Run the Solution

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