来自Deitel《Java编程指南》第10版的练习:
2.30(分隔整数中的数字)编写一个应用程序，输入用户的一个由5位数字组成的数字，将该数字分隔成单独的数字，并将每个数字间隔3个空格的数字打印出来。例如，如果用户输入数字42339，程序应该输出
4 2 3 3 9
假设用户输入了正确的位数。当您输入一个超过五位数字的数字时会发生什么?当您输入少于五位数的数字时会发生什么?[提示:你可以用本章学到的技巧来做这个练习。你需要同时使用除法和提醒操作来"剔除"每一个数字。]
有人能告诉我应该如何使用除法和提醒运算符"挑选"单个整数吗?
编辑:控制结构(if/else等)还不允许，这些将在以后的章节中探讨。
你知道这个数字是5位数长
number / 10 000 to retrieve the first digit.
number = reminder
number / 1000 to retrieve the second digit.
number = reminder
number / 100 to retrieve the third digit.
number = reminder
number / 10 to retrieve the fourth digit.
and reminder is the 5th one.
以下是输入
后按相同顺序显示数字的答案
import java.util.Scanner;
public class oddMethod {
public static void main(String[] args) {
System.out.println("Enter start number:");
int number=getNumber();
int last=Reverse1stTime(number);
System.out.println("Digit You Enter:"+last);
}
private static int getNumber() {
Scanner sr = new Scanner(System.in);
return sr.nextInt();
}
private static int Reverse1stTime(int number)
{ int digit=0;
int reverse=0;
while(number>0)
{
digit=number%10;
reverse=reverse*10+digit;
number=number/10;
}
return reverseAgain(reverse);
}
private static int reverseAgain(int number)
{ int digit=0;
int reverse=0;
while(number>0)
{
digit=number%10;
System.out.println(digit);
reverse=(reverse*10+digit);
number=number/10;
}
return reverse;
}
}
Input 12345
Output 12345
关于除法的小提示-你可以除以10，然后看一下，这个操作给出了什么…此外，如果你想学习编程，你必须推断。
我也刚刚开始使用java和这本书，这是为我做了这一切的代码。如果我做了一些奇怪的事情，请原谅我…:)
import java.util.Scanner;
public class SeparateNumber
{
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int nr, nr1, nr2, nr3, nr4, nr5;
System.out.print("Enter a number with 5 digits: ");
nr = in.nextInt();
nr1 = nr / 10000;
nr2 = (nr % 10000) / 1000;
nr3 = ((nr % 10000) % 1000) / 100;
nr4 = (((nr % 10000) % 1000) % 100) / 10;
nr5 = (((nr % 10000) % 1000) % 100) % 10;
System.out.printf("%d%s%d%s%d%s%d%s%d%n", nr1, " ", nr2, " ", nr3, " ", nr4, " ", nr5);
}
}
试试这个:
import java.util.*;
public class DigitsDisplay
{
public static void main (String[] args)
{
Scanner input = new Scanner (System.in);
int digit;
System.out.print("Enter a positive number: ");
digit = input.nextInt();
int power = 1;
while (power <= digit) {
power *= 10;
}
power /= 10;
while (power > 0) {
System.out.println(digit/power);
digit %= power;
power /= 10;
}
}
}
试试这样
String str1 = "";
int a = 12345;
while(a>0)
{
int b = a%10;
str1 = str1 + String.valueOf(b+" ");
a = a/10;
}
StringBuilder str = new StringBuilder(str1);
System.out.println(str.reverse());
下面的代码处理对整数范围内的任何int进行分割。
步骤:
- 将int转换为String
- 使用Integer.parseInt 将String的每个字符转换为整型
- 在int[]中存储整型数字
- 打印int []
示例代码:
import java.util.*;
public class SplitDigits{
public static void main(String args[]) throws Exception {
System.out.println("Enter number:");
Scanner sc = new Scanner(System.in);
int number = sc.nextInt();
System.out.println("You have entered:"+number);
String str = String.valueOf(number);
int length = str.length();
if ( length > 0){
int[] digits = new int[length];
for ( int i=0; i < length; i++){
digits[i] = Integer.parseInt(String.valueOf(str.charAt(i)));
}
for ( int i=0; i < digits.length; i++){
System.out.println("Digits:"+digits[i]);
}
}
}
}
java SplitDigits
Enter number:
123456789
You have entered:123456789
Digits:1
Digits:2
Digits:3
Digits:4
Digits:5
Digits:6
Digits:7
Digits:8
Digits:9
import java.util.Scanner;
public class DigitSeparator{
public static void main(String[] args){
Scanner input = new Scanner(System.in);
System.out.print("Enter a 5 digit number: ");
int number = input.nextInt();
System.out.print((number / 10000)+ " ");
int divider = 10000;
int mod = number % 10000;
for(int i = 1; i <= 4; i++){
divider /= 10;
System.out.print( mod/divider +" ");
mod %= divider;
}
System.out.println();
}
}
first import java.util.Scanner; berfore your
class.
and write this code in your main method.
Scanner input = new Scanner(System.in);
System.out.print("Enter a five digit number: ");
int number = input.nextInt();
int first_digit = number / 10000;
int second_digit = (number % 10000) / 1000 ;
int third_digit = (number % 1000) / 100;
int fourth_digit = (number % 100) / 10;
int fifth_digit = (number % 10);
System.out.printf("%d %d %d %d
%d%n", first_digit, second_digit, third_digit, fourth_digit, fifth_digit);
package chapter1;
import java.util.Scanner;
public class Exercise3 {
public static void main (String[] args){
Scanner scan = new Scanner (System.in);
System.out.print ("Enter a number that consist of 5 digits: ");
int num =scan.nextInt();
int digit1 =num / 10000;
int digit2 =(( num % 10000) / 1000 ); // the modulus answer of num/10000 is divided by 1000
int digit3 =( ( num % 1000) / 100 );
int digit4 = ( ( num% 100 ) / 10 );
int digit5 = ( num % 10);
System.out.print (digit1+"t");
System.out.print(digit2+"t");
System.out.print(digit3+"t");
System.out.print(digit4+"t");
System.out.println(digit5+"t");
}
}
答案是:
//your package name
import java.util.Scanner; //for input the userin
public class SeperateDigit {
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
System.out.printf("Enter a 5 digit number: ");
int number = input.nextInt();
int number1 = number/100000;
int arrange = number%10000;
int number2 = arrange/1000;
int number3 = (arrange % 1000) /100;
int number4 =(( arrange % 1000) % 100) / 10;
int number5 = ((arrange % 1000) % 100) % 10;
System.out.printf("%d %d %d %d %d", number1,number2,number3,number4, number5);
}
}
and Result is
Enter a 5 digit number: 422339
4 2 3 3 9