01 public String helloName(String name) {
  String s = "Hello " + name + "!";
  return s;
}

02 public String makeAbba(String a, String b) {
  String s = a + b + b + a;
  return s;
}

03 public String makeTags(String tag, String word) {
  String openingTag = "<" + tag + ">";
  String closingTag = "</" + tag + ">";
  String s = openingTag + word + closingTag;
  return s;
}

04 public String makeOutWord(String out, String word) {
  String out1 = out.substring(0,2);
  String out2 = out.substring(2);
  String s = out1 + word + out2;
  return s;
}

05 public String extraEnd(String str) {
  int len = str.length();
  String last2 = str.substring(len-2);
  String s = last2 + last2 + last2;
  return s;
}

06 public String firstTwo(String str) {
  int len = str.length();
  String first2 = "";
  if (len < 2) {
    first2 = str;
  }
  if (len >= 2) {
    first2 = str.substring(0,2);
  }
  return first2;
}

06 public String firstTwo(String str) {
  int len = str.length();
  String first2 = str; // default if len < 2
  if (len >= 2) {
    first2 = str.substring(0,2);
  }
  return first2;
}

07 public String firstHalf(String str) {
  int len = str.length();
  int mid = len / 2;
  String half1 = str.substring(0,mid);
//String half2 = str.substring(mid);
  return half1;
}

08 public String withoutEnd(String str) {
  int len = str.length();
  String s = str.substring(1,len-1);
  return s;
}

09 public String comboString(String a, String b) {
  String combo = "";
  int lenA = a.length();
  int lenB = b.length();
  if (lenA < lenB) {
    combo = a + b + a;
  }
  if (lenB < lenA) {
    combo = b + a + b;
  }
  return combo;
}

09 public String comboString(String a, String b) {
  String shorter = "";
  String longer = "";
  int lenA = a.length();
  int lenB = b.length();
  if (lenA < lenB) {
    shorter = a;
    longer =  b;
  }
  if (lenB < lenA) {
    shorter = b;
    longer =  a;
  }
  String combo = shorter + longer + shorter;
  return combo;
}

09 public String comboString(String a, String b) {
  String combo = a + b + a; // default: IF a is shorter
  int lenA = a.length();
  int lenB = b.length();
  if (lenB < lenA) { 
    combo = b + a + b; // IF b is shorter
  }
  return combo;
}

09 public String comboString(String a, String b) {
  String shorter = a; // default
  String longer = b; // default
  int lenA = a.length();
  int lenB = b.length();
  if (lenB < lenA) { // IF b is shorter !
    shorter = b;
    longer = a;
  }
  String combo = shorter + longer + shorter;
  return combo;
}

10 public String nonStart(String a, String b) {
  String a1 = a.substring(1);
  String b1 = b.substring(1);
  String s = a1 + b1;
  return s;
}

11 public String left2(String str) {
  String left2 = str.substring(0,2);
  String rest = str.substring(2);
  String s = rest + left2;
  return s;
}

12 public String right2(String str) {
  int len = str.length();
  String right2 = str.substring(len-2);
  String rest = str.substring(0,len-2);
  String s = right2 + rest;
  return s;
}

// if front is true, return the FIRST character
// if front is false, (i.e. !front), return the LAST character
13 public String theEnd(String str, boolean front) {
  String s = "";
  if (front) {
    s = str.substring(0,1);
  }
  if (!front) {
    int len = str.length();
    s = str.substring(len-1);
  }
  return s;
}

// !front, returning the last character, is the DEFAULT
13 public String theEnd(String str, boolean front) {
  int len = str.length();
  String s = str.substring(len-1);
  if (front) {
    s = str.substring(0,1);
  }
  return s;
}

// front, returning the first character, is the DEFAULT
13 public String theEnd(String str, boolean front) {
  String s = str.substring(0,1);
  if (!front) {
    int len = str.length();
    s = str.substring(len-1);
  }
  return s;
}

14 public String withouEnd2(String str) {
  int len = str.length();
  String s = "";
  if (len >= 2) {
    s = str.substring(1,len-1);
  }
  return s;
}

15 public String middleTwo(String str) {
  int len = str.length();
  int mid = len / 2;
  String s = str.substring(mid-1,mid+1);
  return s;
}

16 public boolean endsLy(String str) {
  boolean ends = false;
  if ( str.endsWith("ly") ) {
    ends = true;
  }
  return ends;
}

16 public boolean endsLy(String str) {
  boolean ends = false;
  int len = str.length();
  if ( str.startsWith("ly",len-2) ) {
    ends = true;
  }
  return ends;
}

16 public boolean endsLy(String str) {
  boolean ends = false;

  int len = str.length();
  if (len >= 2) {
    String last2 = str.substring(len-2);
    if ( last2.equals("ly") ) {
      ends = true;
    }
  }

  return ends;
}

17 public String nTwice(String str, int n) {
  int len = str.length();
  String firstN = str.substring(0,n);
  String lastN = str.substring(len-n);
  String s = firstN + lastN;
  return s;
}

// this is a tough one!
18 public String twoChar(String str, int index) {
  int len = str.length();
  String s = str.substring(0,2);
  if (0 <= index && index <= len-2) {
    s = str.substring(index,index+2);
  }
  return s;
}

19 public String middleThree(String str) {
  int len = str.length();
  int mid = len / 2;
  String s = str.substring(mid-1,mid+2);
  return s;
}

20 public boolean hasBad(String str) {
  boolean bad = false;
  if ( str.startsWith("bad") ) {
    bad = true;
  }
  if ( str.startsWith("bad",1) ) {
    bad = true;
  }
  return bad;
}

20 public boolean hasBad(String str) {
  boolean bad = false;
  if ( str.startsWith("bad") || str.startsWith("bad",1) ) {
    bad = true;
  }
  return bad;
}

// the long and inefficient way
20 public boolean hasBad(String str) {
  boolean bad = false;
  int len = str.length();
  if (len >= 3) {
    String first3 = str.substring(0,3);
    if ( first3.equals("bad") ) {
      bad = true;
    }
  }
  if (len >= 4) {
    String second3 = str.substring(1,4);
    if ( second3.equals("bad") ) {
      bad = true;
    }
  }
  return bad;
}

21 public String atFirst(String str) {
  String s = "";
  int len = str.length();
  if (len == 0) {
    s = "@@";
  }
  if (len == 1) {
    s = str + "@";
  }
  if (len >= 2) {
    s = str.substring(0,2);
  }
  return s;
}

21 public String atFirst(String str) {
  String s = "@@"; // default for empty string
  int len = str.length();
  if (len == 1) {
    s = str + "@";
  }
  if (len >= 2) {
    s = str.substring(0,2);
  }
  return s;
}

22 public String lastChars(String a, String b) {
  String s = "";
  int lenA = a.length();
  int lenB = b.length();

  String firstA = "@";
  String lastB = "@";

  if (lenA >=1) {
    firstA = a.substring(0,1);
  }
  if (lenB >= 1) {
    lastB = b.substring(lenB-1);
  }
  
  s = firstA + lastB;
  return s;
}

23 public String conCat(String a, String b) {
  String s = a + b;
  
  int lenA = a.length();
  if (lenA >= 1) {
    String lastA = a.substring(lenA-1);
    if (b.startsWith(lastA) ) {
      s = a + b.substring(1);
    }
  }
  
  return s;
}

23 public String conCat(String a, String b) {
  String s = a + b;
  
  int lenB = b.length();
  if (lenB >= 1) {
    String firstB = b.substring(0,1);
    if (a.endsWith(firstB) ) {
      s = a + b.substring(1);
    }
  }
  
  return s;
}


24 public String lastTwo(String str) {
  int len = str.length();
  String s = str;
  if (len >= 2) {
    String last = str.substring(len-1);
    String secondToLast = str.substring(len-2, len-1);
    String rest = str.substring(0,len-2);
    s = rest + last + secondToLast;
  }
  return s;
}

25 public String seeColor(String str) {
  String clr = "";
  if ( str.startsWith("red") ) {
    clr = "red";
  }
  if ( str.startsWith("blue") ) {
    clr = "blue";
  }
  return clr;
}

25 public String seeColor(String str) {
  final String CLR1 = "red";
  final String CLR2 = "blue";
  String clr = "";
  if ( str.startsWith(CLR1) ) {
    clr = CLR1;
  }
  if ( str.startsWith(CLR2) ) {
    clr = CLR2;
  }
  return clr;
}

26 public boolean frontAgain(String str) {
  boolean again = false;
  
  int len = str.length();
  if (len >= 2) {
    String first2 = str.substring(0,2);
    if ( str.endsWith(first2) ) {
      again = true;
    }
  }
  
  return again;
}

27 public String minCat(String a, String b) {
  String s = a + b;
  int lenA = a.length();
  int lenB = b.length();
  if (lenA != lenB) {
    int minLen = Math.min(lenA,lenB);
    String aMin = a.substring(lenA-minLen);
    String bMin = b.substring(lenB-minLen);
    s = aMin + bMin;
  }
  return s;
}

27 public String minCat(String a, String b) {
  String s = a + b;
  int aLen = a.length();
  int bLen = b.length();
  if (aLen < bLen) {
    s = a + b.substring(bLen-aLen);
  }
  if (bLen < aLen) {
    s = a.substring(aLen-bLen) + b;
  }
  return s;
}

28 public String extraFront(String str) {
  int len = str.length();
  String s = "";
  if (len < 2) {
    s = str + str + str;
  }
  if (len >= 2) {
    String front = str.substring(0,2);
    s = front + front + front;
  }
  return s;
}

28 public String extraFront(String str) {
  String s = str + str + str;
  int len = str.length();
  if (len >= 2) {
    String front = str.substring(0,2);
    s = front + front + front;
  }
  return s;
}

28 public String extraFront(String str) {
  int len = str.length();
  int stopPos = Math.min(2,len);
  String front = str.substring(0,stopPos);
  String copies3 = front + front + front;
  return copies3;
}

29 public String without2(String str) {
  String s = str;
  int len = str.length();
  if (len >= 2) {
    String first2 = str.substring(0,2);
    if (str.endsWith(first2)) {
      s = str.substring(2);
    }
  }
  return s;
}

// use frontAgain()!!!
29b public String without2(String str) {
  String s = str;
  if ( frontAgain(str) ) {
    s = str.substring(2);
  }
  return s;
}

29b public boolean frontAgain(String str) {
  boolean again = false;
  
  int len = str.length();
  if (len >= 2) {
    String first2 = str.substring(0,2);
    if ( str.endsWith(first2) ) {
      again = true;
    }
  }
  
  return again;
}

30 public String deFront(String str) {    
  String s = "";

  String first = "";
  String second = "";
  String rest = str.substring(2);

  if (str.startsWith("a") ) {
    first = "a";
  }
  if (str.startsWith("b",1) ) {
    second = "b";
  }
  
  s = first + second + rest;
  return s;
}


31 public String startWord(String str, String word) {
  String s = "";
  String word1 = word.substring(1);
  if ( str.startsWith(word1,1) ) {
    int lenW = word.length();
    s = str.substring(0,lenW);
  }
  return s;
}

32 public String withoutX(String str) {
  String s = str;
  if (s.startsWith("x")) { // s, not str !!!
    s = s.substring(1);
  }
  if (s.endsWith("x")) {
    int len = s.length();
    s = s.substring(0,len-1);
  }
  return s;
}

33 public String withoutX2(String str) {
  String s = str;
  
  // The order matters!
  // You have to check the 2nd character FIRST.
  // If you check the 1st character FIRST
  // and then delete it because it's an "x",
  // the entire string will be shifted one position to the left.
  // The result: the 2nd character is now at the 1st position!

  // Check the 2nd character
  if (s.startsWith("x",1)) {
    s = s.substring(0,1) + s.substring(2);
  }
  
  // Check the 1st character
  if (s.startsWith("x")) {
    s = s.substring(1);
  }
  return s;
}

33 public String withoutX2(String str) {
  String s = "";

  String first = "";
  String second = "";
  String rest = "";
  
  int len = str.length();
  if (len >= 2) {
    rest = str.substring(2);
  }

  if (!str.startsWith("x") && len >= 1) {
    first = str.substring(0,1);
  }
  if (!str.startsWith("x",1) && len >= 2) {
    second = str.substring(1,2);
  }
  
  s = first + second + rest;
  return s;
}