java 方法学习

手写随机代码

public class suiji
{
private static final int N = 200;
private static final int LEFT = 40;
private static final int RIGHT = 10000;
private static long x0 = 1L;
private long a = 1103515245L;
private long c = 12345L;
private long m = 2147483648L;
private long rand ( long r )
{
r = ( r * a + c ) % m;//Xn+1=(aXn + c)mod m
return r;
}
private long little ( int a, int b, long rand )
{
return a + rand % ( b - a + 1 );
}
private void recursion ( int count, long rand )
{
if (count >= N)
{
return;
}
rand = rand (rand);
long r = little (LEFT, RIGHT, rand);
System.out.print (r + "\n");
recursion (++count, rand);
}
public static void main ( String[] args )
{
sgg recur = new sgg ();
recur.recursion (0, x0);
}
}

2.请看以下代码，你发现了有什么特殊之处吗？

相同函数名，数据类型不同与调用的函数对应。

计算组合数

import java.util.*;
public class sgg {
public static void main(String[] args) {// TODO Auto-generated method stub
Scanner in = new Scanner(System.in);
System.out.print("please input ：");
int n = in.nextInt();
System.out.print("please input：");
int k = in.nextInt();

int C = sgg(n)/(sgg(k)*sgg(n - k));
System.out.println("result is :"+C);
}

public static int sgg(int n)
{
  int s = 0;
  if(n < 0)
   System.out.println("error!");
  else if(n == 1||n == 0)
   s = 1;

  else
   s = n * sgg(n -1);
  return s;
  }
}

import java.util.Scanner;
public class sgg {
public static void main(String[] args) {// TODO Auto-generated method stub

  Scanner in = new Scanner(System.in);
  System.out.print("please input：");
  int n = in.nextInt();
  System.out.print("please input ：");
  int k = in.nextInt();

int f = sgg(n,k);
System.out.println(" reaselt is： "+f);
}

public static int sgg(int n,int k)
{
  int f = 0;
  if(n == 1||k == 0||n == k)
   f = 1;
  else
   f = sgg(n - 1,k - 1) + sgg(n - 1,k);
  return f;
  }
}

import java.util.Scanner;
public class ditui {
public static void main(String[] args) {// TODO Auto-generated method stub
  Scanner in = new Scanner(System.in);
  System.out.print("please input：");
  int n = in.nextInt();
  System.out.print("please input ：");
  int k = in.nextInt();
  System.out.println("reasult is:"+sgg(n,k));
  in.close();
  }
public static int sgg(int m,int n)
{
  if(m<0||n<0||m<n)
   return 0;
  if(m==n)
   return 1;
  if(n==1)
   return m;
  return sgg(m-1,n)+sgg(m-1,n-1);
  }
}

汉诺塔用JAVA实现

public class TowersOfHanoi
{
   // recursively move disks between towers
   public static void solveTowers( int disks, int sourcePeg,
      int destinationPeg, int tempPeg )
   {
      // base case -- only one disk to move
      if ( disks == 1 )
      {
         System.out.printf( "\n%d --> %d", sourcePeg, destinationPeg );
         return;
      } // end if

// recursion step -- move (disk - 1) disks from sourcePeg
// to tempPeg using destinationPeg
solveTowers( disks - 1, sourcePeg, tempPeg, destinationPeg );

// move last disk from sourcePeg to destinationPeg
System.out.printf( "\n%d --> %d", sourcePeg, destinationPeg );

// move ( disks - 1 ) disks from tempPeg to destinationPeg
solveTowers( disks - 1, tempPeg, destinationPeg, sourcePeg );
} // end method solveTowers

public static void main( String[] args )
   {
      int startPeg = 1; // value 1 used to indicate startPeg in output
      int endPeg = 3; // value 3 used to indicate endPeg in output
      int tempPeg = 2; // value 2 used to indicate tempPeg in output
      int totalDisks = 3; // number of disks

      // initial nonrecursive call: move all disks.
      solveTowers( totalDisks, startPeg, endPeg, tempPeg );
   } // end main
} // end class TowersOfHanoi

输出结果：

判断字符串是否为回文数

import java.util.*;
public class sgg {
public static void main(String[] args) {
// TODO Auto-generated method stub
String str="";
System.out.println("请输入一个字符串:");
Scanner in=new Scanner(System.in);
str=in.nextLine();
StringBuffer sb=new StringBuffer(str);
sb.reverse();
int n=0;
for(int i=0;i<str.length();i++){
  if(str.charAt(i)==sb.charAt(i))
   n++;
  }

if(n==str.length())
  System.out.println(str+"是回文!");
else
  System.out.println(str+"不是回文!");
}
}

巴特西

java 方法学习

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