一、方法重载
1 public class text {
2
3 public static void main(String[] args) {
4 System.out.println("The square of integer 7 is " + square(7));
5 System.out.println("
The square of double 7.5 is " + square(7.5));
6 }
7 public static int square(int x) {
8 return x * x;
9 }
10 public static double square(double y) {
11 return y * y;
12 }
13 }
方法可以重载，但方法名不变，返回值类型和参数类型可以变。
二、组合数计算
1、使用组合数公式利用n!来计算
1 //使用组合数公式利用n!来计算
2 public class CombinatorialNumber {
3 public static void main(String[] args) {
4 int upNumber=3;
5 int downNumber=6;
6 System.out.println("C["+downNumber+"]["+upNumber+"]="+
7 combNumCal(upNumber,downNumber));
8 }
9 public static int combNumCal(int upN,int downN){
10 if(upN==0||upN==downN)
11 return 1;
12 return f(downN)/(f(upN)*f(downN-upN));
13 }
14 public static int f(int x){ //计算阶乘
15 if(x==1) return 1;
16 else return x*f(x-1);
17 }
18 }
2、使用递归的方法用组合数递推公式计算
1 //使用递归的方法用组合数递推公式计算
2 class CombinatorialNumber {
3
4 public static void main(String[] args) {
5 int upNumber=2;
6 int downNumber=5;
7 System.out.println("C["+downNumber+"]["+upNumber+"]="+
8 combNumCal(upNumber,downNumber));
9 }
10 public static int combNumCal(int upN,int downN){
11 if(upN==0||downN==upN)
12 return 1;
13 return combNumCal(upN-1,downN-1)+combNumCal(upN,downN-1);
14 }
15 }
三、汉诺塔问题
1 public class TowersOfHanoi {
2
3 public static void main(String[] args) {
4 int disks=3; //盘子总数
5 int sourceColumn=1; //第一个珠子 即所有盘子出事的位置
6 int secondColumn=2; //盘子中转的柱子
7 int finalColumn=3; //盘子最终的位置
8 SolveHanoi(disks,sourceColumn,secondColumn,finalColumn);
9 }
10 public static void SolveHanoi(int disk,int first,int second,int third){
11 if(disk==1)
12 System.out.println(first+" ---> "+third);
13 else{
14 SolveHanoi(disk-1,first,third,second);
15 System.out.println(first+" ---> "+third);
16 SolveHanoi(disk-1,second,first,third);
17 }
18 }
19 }
