java经典问题——求正整数的位数

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题目：给一个不多于5位的正整数，要求：一、求它是几位数，二、逆序打印出各位数字。

public class Number {int number;State current;int count;int[] charInNumber;public Number() {current = new OneState();}public int getNumber() {return number;}public void setNumber(int number) {this.number = number;}public State getCurrent() {return current;}public void setCurrent(State current) {this.current = current;}public void getCount(){current.getCount(this);}//求每位数字public void getChars(){charInNumber = new int[count];int temp = number;if(count >= 2){for(int i = 0; i < count; i ++){charInNumber[i] = temp / (getValue(count - 1 - i));temp = temp % (getValue(count - 1 - i));if(temp < 10){charInNumber[i + 1] = temp;break;}}}else{charInNumber[0] = temp;}}//求十的阶乘，感觉好蠢的方法public int getValue(int count){int value = 1;for(int i = 0; i < count; i ++){value = value * 10;}return value;}}

public abstract class State {public abstract void getCount(Number number);}

public class OneState extends State {@Overridepublic void getCount(Number number) {if(number.getNumber() < 10 ){number.count = 1;number.getChars();}else{number.setCurrent(new TwoState());number.getCount();}}}

public class TwoState extends State {@Overridepublic void getCount(Number number) {if(number.getNumber() < 100){number.count = 2;number.getChars();}else{number.setCurrent(new ThreeState());number.getCount();}}}

public class ThreeState extends State {@Overridepublic void getCount(Number number) {if(number.getNumber() < 1000){number.count = 3;number.getChars();}else{number.setCurrent(new FourState());number.getCount();}}}

public class FourState extends State {@Overridepublic void getCount(Number number) {if(number.getNumber() < 10000){number.count = 4;number.getChars();}else{number.setCurrent(new FiveState());number.getCount();}}}

public class FiveState extends State {@Overridepublic void getCount(Number number) {if(number.getNumber() < 100000){number.count = 5;number.getChars();}}}

public class Practise24 {private void getResult(){System.out.println("请输入一个不多于5位的正整数");Scanner scan = new Scanner(System.in);int input = scan.nextInt();Number number = new Number();number.setNumber(input);number.getCount();System.out.println(number.getNumber() + " 是 " + number.count +"位数");System.out.println();for(int i = number.count - 1; i >= 0; i --){System.out.print(" "+number.charInNumber[i]);}}public static void main(String[] args) {(new Practise24()).getResult();}}