Go Program to Find the Length of a String Without Using Built-in Functions

1. Introduction

While Go provides a built-in len() function to fetch the length of a string, understanding how to manually compute this can be an enlightening exercise. In this guide, we'll learn how to create a Go program to find the length of a string without leaning on built-in functions.

2. Program Overview

Our Go program will:

1. Prompt the user to input a string.

2. Traverse the string character by character to compute its length.

3. Exhibit the calculated length to the user.

3. Code Program

// We embark on our journey with the main package declaration.
package main

// The fmt package is summoned for its input-output superpowers.
import "fmt"

// Function to manually compute the length of a string.
func stringLength(str string) int {
    length := 0
    for range str {
        length++
    }
    return length
}

// The heart and soul of our program - the main function.
func main() {
    var inputString string

    // A nudge for the user to provide their string.
    fmt.Print("Enter your string: ")
    fmt.Scanln(&inputString)

    // Unveiling the magic of our manual length computation.
    fmt.Printf("The length of the string \"%s\" is: %d\n", inputString, stringLength(inputString))
}

Output:

For the sake of illustration, if a user submits the string GoLang, the program's revelation will be:
The length of the string "GoLang" is: 6

4. Step By Step Explanation

1. Package and Import: We start by declaring package main, marking the entry point of our program. The fmt package is invoked to manage the program's input and output dynamics.

2. Manual Length Computation Function: The stringLength function iterates over each character in the string using a for-range loop. With every iteration, we increment a counter, ultimately returning its value as the string's length.

3. User Interaction & Result: The variable inputString holds the user's input. After prompting and fetching the string from the user, the program calls the stringLength function and displays the resultant length.