/**  * Created by Sandy.Liu on 2018/7/19.  * Thinking in java, version 4, chapter 4, practice 1  * Write a program to print from 1 to 100  */ public class Chap4Prac1Printfrom1To100 {
      public static void main(String[] args){
          for(int i=1;i<=100;i++)             P.print(i+" ");     } }

/**  * Created by Sandy.Liu on 2018/7/19.  * Thinking in java, chapter 4, practice 2  * Write a program which generating 25 random int numbers. Use if-else statement to classify it as  * greater than, less than or equal to a second randomly generated value.  */ import java.util.*; public class Chap4Prac2Generate25int {
      public static void main(String[] args){
          Random ran1 = new Random();         Random ran2 = new Random();         P.print("ran1: "+ran1);         P.print("ran2: "+ran2);         for(int i=0;i<25;i++){
              int x = ran1.nextInt();             int y = ran2.nextInt();             if(x>y)                 P.print(x+">"+y);             else if(x

import java.util.Random; /**  * Created by Sandy.Liu on 2018/7/19.  * Thinking in java, version 4, chapter 4, practice 3  */ import java.util.*; public class Chap4Prac3 {
      public static void main(String[] args){
          Random ran3 = new Random();         Random ran4 = new Random();         while(true){
              int x = ran3.nextInt(10);             int y = ran4.nextInt(10);             if(x>y)                 P.print(x+">"+y);             else if(x

/**  * Created by Sandy.Liu on 2018/7/19.  * Thinking in java, version 4, chapter 4, practice 4  * Write a program using two nested for loops and the modules operator(%) to detect and print  * prime numbers  */ public class Chap4Prac4For {
      public static void main(String[] args){
          for(int i = 1;i<100;i++){
              int factor = 0;             for(int j=1;j<=i;j++){
                  if(i%j==0)                     factor++;             }             if(factor<=2)                 P.print(i);         }     } }

/**  * Created by Sandy.Liu on 2018/7/19.  * Thinking in java, version 4, chapter 4, practice 5  */ public class Chap4Prac5 {
      static void binaryPrint(int q){
          if(q==0) P.print(0);         else{
              int nlz = Integer.numberOfLeadingZeros(q);             q<<=nlz;             for(int p=0;p<32-nlz;p++){
                  int n = (Integer.numberOfLeadingZeros(q)==0)?1:0;                 System.out.println(n);                 q<<=1;             }         }         P.print("");     }     public static void main(String[] args){
          int i=1+4+16+64;         int j = 2+8+32+128;         int k = 0x100;         int m = 0;         P.print("Using Integer.toBinaryString(): ");         P.print("i =  "+Integer.toBinaryString(i));         P.print("j = "+Integer.toBinaryString(j));         P.print("k = "+Integer.toBinaryString(k));         P.print("m= "+Integer.toBinaryString(m));         P.print("i & j = "+(i&j)+"="+Integer.toBinaryString(i&j));         P.print("i | j = "+(i|j)+"="+Integer.toBinaryString(i|j));         P.print("i ^ j = "+(i^j)+"="+Integer.toBinaryString(i^j));         P.print("~i = "+Integer.toBinaryString(~i));         P.print("~j = "+Integer.toBinaryString(~j));         P.print("Using binaryPrint():");         P.print("i = "+i+" = ");         System.out.print(i);         P.print("j = "+j+" = ");         System.out.print(j);         P.print("k = " + k + " = ");         System.out.print(k);         P.print("m = " + m + " = ");         System.out.print(m);         P.print("i & j = " + (i & j) + " = ");         System.out.print(i & j);         P.print("i | j = " + (i | j) + " = ");         System.out.print(i | j);         P.print("i ^ j = " + (i ^ j) + " = ");         System.out.print(i ^ j);         P.print("~i = " + ~i + " = ");         System.out.print(~i);         P.print("~j = " + ~j + " = ");         System.out.print(~j);     } }

/**  * Created by Sandy.Liu on 2018/7/22.  * Thinking in java, version 4, chapter 4, practice 6  * Modify method test(), make them accept two other parameters begin and end, check if  * testval is between begin and end.  */ public class Chap4Prac6 {
      static int test(int testval, int begin, int end){
          if (end
    
     =begin))             return +1;         else if((testval
     
      end))             return -1;         else             P.print("exceptional case");             return 13;     }     public static void main(String[] args){
          test(10, 5,4);//begin
      
       end     } }
      
     
    

/**  * Created by Sandy.Liu on 2018/7/22.  * Thinking in java, version 4, chapter 4, practice 7  * Modify excise 1, use break to make program exists at value 99  */ public class Chap4Prac7{
      static void test(int x){
          for(int i=0;i<=x;i++){
              if(i==99)                 break;             P.print(i);         }     }     static void test1(int x){
          for(int i=0;i<=x;i++){
              if(i==99)                 return;             P.print(i);         }     }     public static void main(String[] args) {
          test(100);         test1(1000);     } }

/**  * Created by Sandy.Liu on 2018/7/23.  * Thinking in java, version 4, chapter 4, practice 8  * Create a switch statement that prints a message for each case, and put the switch inside a for loop  * to try each case. Put a break after each case and test it. And then remove the breaks and test again.  */ public class Chap4Prac8Switch {
      public static void main(String[] args){
          for(int i = 0;i<100;i++){
              switch (i){
                  case 0: P.print("zero");break;                 case 1: P.print("one");break;                 case 2: P.print("two");break;                 case 3: P.print("three");break;                 default: P.print(i+"more than three");             }         }     } }

import java.lang.reflect.Array; import java.util.ArrayList; /**  * Created by Sandy.Liu on 2018/7/23.  * Thinking in java, version 4, chapter 4, practice 9  * A Fibonacci sequence is the sequence of numbers 1, 1, 2, 3, 5, 8, 13, 21, 34, and so on,  * each number (from the third one ) is the sum of the previous two numbers.  * Create a method that takes a integer as parameter,and display all Fibonacci numbers starting  * from the beginning to the gave parameter. e.g., if you run javaFibonacci 5 (where Fibonacci  * is the name of the class) the output will be 1, 1, 2, 3, 5.  */ public class Chap4Prac9Fibonacci {
      static void gFib(int i) {
          if (i <= 0)             P.print("please input a number bigger than 0");         int[] a = new int[i];         if (i <= 2) {
              for (int k = 0; k < i; k++)                 a[k] = 1;         } else {
              a[0] = 1;             a[1] = 1;             for (int j = 2; j < i; j++)                 a[j] = a[j - 2] + a[j - 1];         }         for (int m = 0; m < i; m++){
              System.out.print(a[m]);         }         P.print(" ");     }     public static void main(String[] args){
          gFib(0);         gFib(1);         gFib(2);         gFib(5);         } }

/**  * Created by Sandy.Liu on 2018/7/25.  * Thinking in java, version 4, chapter 4, practice 10  * A vampire number has an even number of digits and is formed by multiplying a pair of numbers  * containing half the number of digits of the result.  * The digits are taken from the original number in any order. Pairs of railing zeros are not  * allowed. Examples include:1260 = 21 * 60, 1827 = 21 * 87,  * 2187 = 27  * 81.  * Write a program that finds all the 4-digit vampire numbers.  */ public class Chap4Prac10VaimpireNumber {
      static int a(int i) {
          return i / 1000;     }     static int b(int i) {
          return (i % 1000) / 100;     }     static int c(int i) {
          return ((i % 1000) % 100) / 10;     }     static int d(int i) {
          return ((i % 1000) % 100) % 10;     }     static int com(int i, int j){
          return i*10+j;     }     static void productTest(int i, int m, int n){
          if(i==m*n){
              P.print(i+"="+m+"*"+n);         }     }     public static void main(String[] args) {
          for(int i = 1001;i<9999;i++){
              productTest(i,com(a(i),b(i)),com(c(i),d(i)));             productTest(i,com(a(i),b(i)),com(d(i),c(i)));             productTest(i,com(a(i),c(i)),com(b(i),d(i)));             productTest(i,com(a(i),c(i)),com(d(i),b(i)));             productTest(i,com(a(i),d(i)),com(b(i),c(i)));             productTest(i,com(a(i),d(i)),com(c(i),b(i)));             productTest(i,com(b(i),a(i)),com(c(i),d(i)));             productTest(i,com(b(i),a(i)),com(d(i),c(i)));             productTest(i,com(b(i),c(i)),com(d(i),a(i)));             productTest(i,com(b(i),d(i)),com(c(i),a(i)));             productTest(i,com(c(i),a(i)),com(d(i),b(i)));             productTest(i,com(c(i),b(i)),com(d(i),a(i)));         }     } }