public class DnaUtilities2{
  public static void main(String [] args){
    char a = 'A';
    boolean value;
    value = isValidBase(a);
    System.out.println(value);

    char value2;
    value2 = watsonCrickComplement(a);
    System.out.println(value2);

    String dnaSequence = "ATT";
    int length = dnaSequence.length();
    System.out.println(length);
    char firstCharacter = dnaSequence.charAt(0);
    char secondCharacter = dnaSequence.charAt(1);
    char thirdCharacter = dnaSequence.charAt(2);

    String value3;
    value3=watsonCrickTripletComplement(dnaSequence);
    System.out.println(value3);


    //System.out.println(a + " gives out :" + value + "\n");

    /*for (int i=1; i<26; i++) {
     a++;
     value = isValidBase(a);
     System.out.println("'" + a + "'" + " gives out :" + value + "\n");
    } */
  }


  public static boolean isValidBase(char x){
      if ((x == 'A')||(x == 'T') || ( x == 'C') || ( x == 'G')){
        return true;
      }
      else{
        return false;
      }
    }
  public static char watsonCrickComplement(char x) {
    /*char a = 'C';
    boolean value;
    value = isValidBase(a);
    System.out.println(value);*/


    if (x =='A'){
      return 'T';

    }
    else if (x == 'T'){
      return 'A';
    }
    else if (x == 'C'){
      return 'G';
    }
    else if (x == 'G') {
      return 'C';
    }
    else {
      return x;

    }

  }


 public static String watsonCrickTripletComplement(String dnaSequence){
   // if length is 3 and all characters are valid -- return complement
   if(dnaSequence == "ATA"){
     return "TAT";
   }
   else{
     return "";
   }


    }
     //it should verify that dnaSequence has exactly 3 characters in it.
    public static int length(){
      int x = 0 ;
      return x;

      }
      //Next verify that each of the 3 characters are valid Watson-Crick complements.
    public static int charAt(int i){
      int y = 0;
      return y;
    }
}