java數據結構單鏈表的實現
1.用接口(Interface)形式實現線性表的ADT的公有方法。
2.接口方法的實現
3.接口方法的類客戶
List.java (List接口):
interface List { // List ADT
public void clear(); // Remove all Objects from list
public void insert(Object item); // Insert Object at curr position
public void append(Object item); // Insert Object at tail of list
public Object remove(); // Remove/return current Object
public void setFirst(); // Set current to first position
public void next(); // Move current to next position
public void prev(); // Move current to prev position
public int length(); // Return current length of list
public void setPos(int pos); // Set current to specified pos
public void setValue(Object val); // Set current Object's value
public Object currValue(); // Return value of current Object
public boolean isEmpty(); // Return true if list is empty
public boolean isInList(); // True if current is within list
public void print(); // Print all of list's elements
} // interface List
class AList implements List { // Array-based list implementation
private static final int defaultSize = 10; // Default array size
private int msize; // Maximum size of list
private int numInList; // Actual number of Objects in list
private int curr; // Position of current Object
private Object[] listArray; // Array holding list Objects
AList() { setup(defaultSize); } // Constructor: use default size
AList(int sz) { setup(sz); } // Constructor: user-specified size
private void setup(int sz) { // Do actual initialization work
msize = sz;
numInList = curr = 0;
listArray = new Object[sz]; // Create listArray
}
public void clear() // Remove all Objects from list
{ numInList = curr = 0; } // Simply reinitialize values
public void insert(Object it) { // Insert Object at current position
//Assert.notFalse(numInList < msize, "List is full");
//Assert.notFalse((curr >= 0) && (curr <= numInList),
// "Bad value for curr");
if (numInList < msize){
System.out.println("List is full");
return;
}
if ((curr < 0) && (curr<numInList)){
System.out.println("Bad value for curr");
return;
}
for (int i=numInList; i>curr; i--) // Shift Objects to make room
listArray[i] = listArray[i-1];
listArray[curr] = it;
numInList++; // Increment list size
}
public void append(Object it) { // Insert Object at tail of list
// Assert.notFalse(numInList < msize, "List is full");
if (numInList >= msize){
System.out.println("List is full");
return;
}
listArray[numInList++] = it; // Increment list size
}
public Object remove() { // Remove and return current Object
//Assert.notFalse(!isEmpty(), "Can't delete from empty list");
//Assert.notFalse(isInList(), "No current element");
Object it = listArray[curr]; // Hold removed Object
for(int i=curr; i<numInList-1; i++) // Shift elements down
listArray[i] = listArray[i+1];
numInList--; // Decrement list size
return it;
}
public void setFirst() { curr = 0; } // Set curr to first position
public void prev() { curr--; } // Move curr to previous position
public void next() { curr++; } // Move curr to next position
public int length() // Return length of list
{ return numInList; }
public void setPos(int pos) // Set curr to specified position
{ curr = pos; }
public void setValue(Object it) { // Set current Object's value
//Assert.notFalse(isInList(), "No current element");
listArray[curr] = it;
}
public Object currValue() { // Return current Object's value
//Assert.notFalse(isInList(), "No current element");
return listArray[curr];
}
public boolean isEmpty() // Return true if list is empty
{ return numInList == 0; }
public boolean isInList() // True if curr is within list
{ return (curr >= 0) && (curr < numInList); }
public void print() { // Print all list's Objects
if (isEmpty()) System.out.println("()");
else {
System.out.print("( ");
for (setFirst(); isInList(); next())
System.out.print(currValue() + " ");
System.out.println(")");
}
}
} // class Alist
AList順序表類的使用,myList.java的實現:
public class myList{
public static void main(String[] args){
testList();
}
public static void testList(){
AList myList = new AList(5);
myList.append(10);
myList.append(20);
myList.append(50);
myList.append(50);
myList.append(50);
myList.append(50);
myList.print();
}
}