12_打印1到最大的N位数

小灰灰 2022-06-08 08:14 162阅读 0赞

## Java版 ##

> 题目：输入数字n，按顺序打印出1到最大的n位十进制数。比如输入3，则打印出1、2、3一直到最大的3位数即999。

public class Print1ToMax {
    
        //对数字进行加1操作
        public static boolean Increment(int[] num){
            boolean isOverflow = false;
            int nTakeOver = 0;
            for(int i=num.length-1; i >= 0;i--){
                int nSum = num[i] +nTakeOver;
                if(i == num.length-1)
                    nSum++;
                if(nSum >= 10){
                    if(i == 0)
                        isOverflow = true;
                    else{
                        nTakeOver = 1;
                        nSum = nSum - 10;
                        num[i] = nSum;
                    }
                }
                else{
                    num[i] = nSum;
                    break;
                }
            }
            return isOverflow;  
        }
    
        public static void PrintNumber(int[] num) {
            boolean isBeginning = true;
            for(int i = 0 ; i< num.length;i++){
                if(isBeginning && num[i] != 0)
                    isBeginning = false;
                if(!isBeginning)
                    System.out.print(num[i]);
                }
            }
    
        //打印从1到最大的n位数
        public static void Test(int n) {
            if(n <= 0)
                System.out.println("Input Error!");
            int[] num = new int[n];
            while(!Increment(num)){
                PrintNumber(num);
                System.out.println();
            }
        }
    
        public static void main(String[] args) {
            Scanner scanner = new Scanner(System.in);
            System.out.print("Please input number:");
            int num = scanner.nextInt();
            Test(num);
            scanner.close();
        }
    }