import 'dart:io';
 
void main() {
    VogalOuConsoante("A");
    VogalOuConsoante("c");
    VogalOuConsoante("1");
    VogalOuConsoante("Nome");
}
 
void VogalOuConsoante(String letra) {
    var chr = letra[0].toLowerCase();
    if ("aeiou".contains(chr)) {
        print("A letra ${letra[0]} é uma vogal");
    } else if ("bcdfghjklmnpqrstuvxyz".contains(chr)) {
        print("A letra ${letra[0]} é uma consoante");
    } else {
        print("${letra[0]} não é uma letra");
    }
}
 
//https://pt.stackoverflow.com/q/573430/101

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