使用Swift语言实现，非常简单，具体代码如下：

func countChars(string: String) -> (vowels: Int,consonants: Int,others: Int) {
    var vowels = 0,consonants = 0,others = 0
    for character in string {
        var char = String(character).lowercaseString
        switch char {
        case "a","e","i","o","u":
            vowels++
        case "b","c","d","f","g","h","j","k","l","m","n","p","q","r","s","t","v","w","x","y","z":
            consonants++
        default:
            others++
        }
    }
    
    return (vowels,consonants,others)
}
let charsInfo = countChars("some arbitrary string!")
println("Vowels:\(charsInfo.vowels),Consonants:\(charsInfo.consonants),Othes:\(charsInfo.others)")

另外：

这代码不是我写的，是官方的例子。我做了一点微小的改动而已。