java课java方法动手动脑

动手动脑：

import java.util.Scanner;

public class Random {

public static void main(String[] args) {
        
        Scanner input=new Scanner(System.in);
        int n;
        System.out.println("输入随机数个数");
        n=input.nextInt();
        int seed=1;
        int c=0;
        int num=0;
        
        for(int i=0;i<n;i++){
        
            seed=(7^5*seed+c)%(2^100);
            num++;
            System.out.print(seed+"  ");
            if(num%10==0) {
            
System.out.println();
            }
            }
    }

}

课后验证1：CalculateN,java

import
java.math.BigInteger;

import
java.util.Scanner;

public class CalculateN
{

/**

* @param args

*/

public static void main(String[] args) {

System.out.print("请输入N：");

Scanner
scanner=new Scanner(System.in);

int number=scanner.nextInt();

System.out.println(number+"!="+calculateN2(number));

}

public static long calculateN(int n) {

if(n==1 || n==0){

return 1;

}

return n*calculateN(n-1);

}

public static BigInteger calculateN2(int n) {

if(n==1 || n==0){

return BigInteger.valueOf(1);

}

return BigInteger.valueOf(n).multiply(calculateN2((n-1)));

}

}

课后测试2：CompareFloatNumber.java

public class CompareFloatNumber {

/**

* @param args

*/

public static void main(String[] args) {

//compare();

compare2();

}

private static void compare() {

double i = 0.0001;

double j = 0.00010000000000000001;

System.out.println(i==j);  //输出：true

}

private static void compare2() {

double i = 0.0001;

double j = 0.00010000000000000001;

if(Math.abs(i-j)<1e-10){

System.out.println("true");

}

else

{

System.out.println("false");

}

}

}

课后测试3：MethodOverload.java

public class MethodOverload {

public static void main(String[] args) {

System.out.println("The square of integer 7 is " + square(7));

System.out.println("\nThe square of double 7.5 is " + square(7.5));

}

public static int square(int x) {

return x * x;

}

public static double square(double y) {

return y * y;

}

}

课后测试4：RandomInt.java

import
javax.swing.JOptionPane;

public class RandomInt {

public static void main( String args[] )

{

int value;

String output = "";

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

value = 1 + (int) ( Math.random() * 6 );

output += value + "  ";

if ( i % 5 == 0 )

output += "\n";

}

JOptionPane.showMessageDialog( null, output,

"20 Random Numbers from 1 to 6",

JOptionPane.INFORMATION_MESSAGE );

System.exit( 0 );

}

}

课后测试5：RollDie.java

import
javax.swing.*;

public class RollDie
{

public static void main( String args[] )

{

int frequency1 = 0, frequency2 = 0,

frequency3 = 0, frequency4 = 0,

frequency5 = 0, frequency6 = 0, face;

// summarize results

for ( int roll = 1; roll <= 6000; roll++ ) {

face = 1 + (int) ( Math.random() * 6 );

switch ( face ) {

case 1:

++frequency1;

break;

case 2:

++frequency2;

break;

case 3:

++frequency3;

break;

case 4:

++frequency4;

break;

case 5:

++frequency5;

break;

case 6:

++frequency6;

break;

}

}

JTextArea outputArea = new JTextArea( 7, 10 );

outputArea.setText(

"Face\tFrequency" +

"\n1\t" + frequency1 +

"\n2\t" + frequency2 +

"\n3\t" + frequency3 +

"\n4\t" + frequency4 +

"\n5\t" + frequency5 +

"\n6\t" + frequency6 );

JOptionPane.showMessageDialog( null, outputArea,

"Rolling a Die 6000 Times",

JOptionPane.INFORMATION_MESSAGE );

System.exit( 0 );

}

}

课后测试6：SquareInt.java

public class SquareInt {

public static void main(String[] args) {

int result;

for (int x = 1; x <= 10; x++) {

result = square(x);

// Math库中也提供了求平方数的方法

// result=(int)Math.pow(x,2);

System.out.println("The square of " + x + " is " + result + "\n");

}

}

// 自定义求平方数的静态方法

public static int square(int y) {

return y * y;

}

}

课后测试7：TestRandom.java

import
java.util.*;

public class TestRandom

{

public static void main(String[] args)

{

Random rand = new Random();

System.out.println("rand.nextBoolean()：" + rand.nextBoolean());

byte[] buffer = new byte[16];

rand.nextBytes(buffer);

System.out.println(Arrays.toString(buffer));

//生成0.0~1.0之间的伪随机double数

System.out.println("rand.nextDouble()：" + rand.nextDouble());

//生成0.0~1.0之间的伪随机float数

System.out.println("rand.nextFloat()：" + rand.nextFloat());

//生成平均值是 0.0，标准差是 1.0的伪高斯数

System.out.println("rand.nextGaussian()：" + rand.nextGaussian());

//生成一个处于long整数取值范围的伪随机整数

System.out.println("rand.nextInt()：" + rand.nextInt());

//生成0~26之间的伪随机整数

System.out.println("rand.nextInt(26)：" + rand.nextInt(26));

//生成一个处于long整数取值范围的伪随机整数

System.out.println("rand.nextLong()：" +  rand.nextLong());

}

}

课后测试8：TestSeed.java

import
java.util.Random;

public class TestSeed

{

public static void main(String[] args)

{

Random r1 = new Random(50);

System.out.println("第一个种子为50的Random对象");

System.out.println("r1.nextBoolean():\t" + r1.nextBoolean());

System.out.println("r1.nextInt():\t\t" + r1.nextInt());

System.out.println("r1.nextDouble():\t" + r1.nextDouble());

System.out.println("r1.nextGaussian():\t" + r1.nextGaussian());

System.out.println("---------------------------");

Random r2 = new Random(50);

System.out.println("第二个种子为50的Random对象");

System.out.println("r2.nextBoolean():\t" + r2.nextBoolean());

System.out.println("r2.nextInt():\t\t" + r2.nextInt());

System.out.println("r2.nextDouble():\t" + r2.nextDouble());

System.out.println("r2.nextGaussian():\t" + r2.nextGaussian());

System.out.println("---------------------------");

Random r3 = new Random(100);

System.out.println("种子为100的Random对象");

System.out.println("r3.nextBoolean():\t" + r3.nextBoolean());

System.out.println("r3.nextInt():\t\t" + r3.nextInt());

System.out.println("r3.nextDouble():\t" + r3.nextDouble());

System.out.println("r3.nextGaussian():\t" + r3.nextGaussian());

Random r4 = new Random(System.currentTimeMillis());

System.out.println("以当前时间为种子的Random对象");

System.out.println("r3.nextBoolean():\t" + r4.nextBoolean());

System.out.println("r3.nextInt():\t\t" + r4.nextInt());

System.out.println("r3.nextDouble():\t" + r4.nextDouble());

System.out.println("r3.nextGaussian():\t" + r4.nextGaussian());

}

}

课后测试9：VariableArgumentsTest.java

import java.awt.*;

import java.awt.event.*;

import java.util.*;

public class VariableArgumentsTest{

public
static double max(double...values)

{

double
largest=Double.MIN_VALUE;

for
(double v:values)

if(v>largest)
largest=v;

return
largest;

}

public
static void main(String args[]) {

System.out.println("Max:"+max(1,11,300,2,3));

}

}