在Windows中，"记事本"文件默认的文件扩展名是".txt"。

2.整体护理的特点有:（   ）

public static void main(String[] args) {

           int x, y=0;

          for(x=1; x<5; x++) y+=x*x;

          System.out.println("y="+y);

 }

public static void main(String[] args) {

          int x, y=0;

          for(x=1; x<10; x++)

               if(x%2==0) y+=x*x;

          System.out.println("y="+y);

 }

public static void main(String[] args) {

         int x=1, y=1;

          while(x++<5) y+=x*x;

          System.out.println("y="+y);

  }

public static void main(String[] args) {

int i=1, s=0;

while(true) {

if(i%2==0) s+=i;

if(i++>=10) break;

}

System.out.println("s="+s);

}

public static void main(String[] args) {

int c0=0, c1=0, c2=0;

for(int x=1; x<=20; x++) {

switch(x%3) {

case 0: c0++; break;

case 1: c1++; break;

case 2: c2++; break;

}

}

System.out.println("c0,c1,c2="+c0+","+c1+","+c2);

}

public class XXK2 {

private int a,b;

public XXK2(int aa, int bb) {a=aa; b=bb;}

public int f1(int x) {

if(x>10) return a+b+3*x;

else return a*b*x;

}

public static void main(String[] args) {

XXK2 x=new XXK2(3,4);

int y=x.f1(8);      

System.out.println("y="+y);

}

}

abstract class Shape {

int a,b;

public Shape(int aa, int bb) {a=aa; b=bb;}

abstract public double area();

}

class Rectangle extends Shape {

public Rectangle(int aa, int bb) {super(aa,bb);}

public double area() {return a*b;}

}

class Triangle extends Shape {

public Triangle(int aa, int bb) {super(aa,bb);}

public double area() {return a*b/2;}

}

public class XXK3 {

public static void main(String[] args) {

Shape x,y;

x=new Rectangle(10,20);

y=new Triangle(10,15);

System.out.println(x.area()+", "+y.area());

}

}

public class XXK4 {

public static void main(String[] args) {

int []a={2,5,8,10,15,20};

int s=0;

for(int i=0; i<a.length; i++) s+=a[i];

System.out.println("s="+s);

}

}

public class XXK4 {

public static void main(String[] args) {

String []a={"xxk","weirong","xucong","xuxiaohua","baojuan"};

int m=0;

for(int i=0; i<a.length; i++) {

int n=a[i].length();

if(n>m) m=n;

}

System.out.println("m="+m);

}

}

interface Shape {

double area();

double girth();

}

class Rectangle implements Shape {

int a,b;

public Rectangle(int aa, int bb) {a=aa; b=bb;}

public double area() {return a*b;}

public double girth() {return 2*(a+b);}

}

public class XXK3 {

public static void main(String[] args) {

Shape x;

x=new Rectangle(5,8);

System.out.println(x.area()+", "+x.girth());

}

}

Public class Test {

Public static void main(String［］ args) {

Vector teamList = new Vector();

teamList.add("Z");

teamList.add("L");

teamList.add("W");

teamList.remove(0);

teamList.remove(0);

System.out.println(teamList.size()+","+teamList.get(0));

}

}

public class XXK4 {

public static void main(String[] args) {

int [][]a={{2,5,8},{3,6,9},{4,5,6}};

int []b=new int[3];

int i,j;

for(i=0; i<a.length; i++)

for(j=0; j<a[i].length; j++)

b[i]+=a[i][j];

for(i=0; i<b.length; i++)

System.out.print(b[i]+" ");

}

}

class ABC {

int a,b;

public ABC(int a, int b) {this.a=a; this.b=b;}

public int compareTo(ABC x) {return a*b-x.a*x.b;}

}

public class XXK5 {

public static void main(String[] args) {

int [][]d={{3,8},{4,6},{5,6},{2,9},{6,7},{5,8}};

ABC []ar=new ABC[d.length];

int i,k=0;

for(i=0; i<ar.length; i++)

ar[i]=new ABC(d[i][0],d[i][1]);

for(i=1; i<ar.length; i++)

if(ar[i].compareTo(ar[k])>0) k=i;

System.out.println("k="+k);

}

}

class ABC {

String name;

double price;

public ABC(String na, double pr) {name=na; price=pr;}

public int compareTo(ABC x) {

if(name.compareTo(x.name)>0) return 1;

if(name.compareTo(x.name)<0) return -1;

else return 0;

}

}

public class XXK5 {

public static void main(String[] args) {

String []s={"apple", "pear", "tangerme", "banana", "grape"};

double []d={3.8, 2.5, 3.2, 4.3, 5.2};

ABC []ar=new ABC[s.length];

int i,k=0;

for(i=0; i<ar.length; i++)

ar[i]=new ABC(s[i],d[i]);

for(i=1; i<ar.length; i++)

if(ar[i].compareTo(ar[k])>0) k=i;

System.out.println(ar[k].name+" "+ar[k].price);

}

}

public class StackTest {

public static void main(String［］ args) {

Stack<Integer> st = new Stack<Integer>();

st.push(new Integer(11));

st.push(new Integer(22));

st.push(new Integer(33));

System.out.println("size is-> "+st.size());

System.out.println("Top is-> "+st.peek());

st.pop();

System.out.println("new Top is-> "+st.peek());

}

}

设集合A={1, 2, 3}，B={2, 3, 4}，C={3, 4, 5}，则A∩(C-B )= {1, 2, 3, 5}．（    ）

设A={2, 3}，B={1, 2}，C={3, 4}，从A到B的函数f={<2, 2>, <3, 1>}，从B到C的函数g={<1，3>, <2，4>}，则Dom(g° f) ={2，3}．（    ）

已知图G中有1个1度结点，2个2度结点，3个3度结点，4个4度结点，则G的边数是15．(    )