💡 Character Frequency Count in a String using Goroutines in Go

In Go, strings are immutable, meaning once a string is created, its value cannot be modified directly. However, we can still analyze and process strings efficiently.

In this example, we will implement a program to calculate the frequency of each character in a string using Goroutines and channels.

🔤 Sample String:

`str := "We often will need to manipulate strings in our messaging app. For example, adding some personalization by using a customer's name within a template"`

📦 Step 1: Define a Struct to Hold Character and Count

type CharFreq struct {
Char rune
Count int
}

📦 Step 2: Declare a Map and Channel

charCh := make(chan CharFreq)
strMap := make(map[string]int)

🔁 Step 3: Iterate Through the String and Count Characters
We will convert all characters to lowercase and ignore spaces and punctuation.

`for _, v := range str {
    // Convert uppercase to lowercase
    if v >= 'A' && v <= 'Z' {
        v += 32
    }

    // Skip spaces and punctuation (optional enhancement)
    if v == ' ' {
        continue
    }

    // Convert rune to string and count
    strMap[v]++
}`

⚙️ Step 4: Use an Anonymous Goroutine to Send Data to Channel

`go func() {
    for i, v := range strMap {
        charCh <- CharFreq{Char: i, Count: v}
    }
    close(charCh)
}()`

📤 Step 5: Read from Channel and Print Results

`for item := range charCh {
    fmt.Printf("Character: %s, Count: %d\n", item.Char, item.Count)
}`

✅ Final Output:
You will get the frequency of each character (excluding spaces) printed via the channel using a concurrent approach.

//output
Character: g, Count: 5
Character: x, Count: 1
Character: e, Count: 14
Character: o, Count: 8
Character: m, Count: 7

Complete implementation link: https://www.programiz.com/online-compiler/0G4nsPTV0NR3B