Character Counter
Count every character in a string using a map[rune]int. A rune is Go's type for a single character. When you loop over a string with range, each value is a rune.
package main
import "fmt"
func main() {
text := "hello, world!"
counts := map[rune]int{}
for _, ch := range text {
counts[ch]++
}
for ch, count := range counts {
fmt.Printf("'%c': %d\n", ch, count)
}
}