如何在循环中平均间隔整数？

Question

我必须根据用户的输入打印一个乘法表。 到目前为止，这是我的代码：

import java.util.Scanner;
public class problem7
{
public static void main (String args[])
{

int n1,n2,n3;
int i1, i2;
char again;
Scanner input=new Scanner(System.in);


System.out.println("Please enter the starting number:");
n1=input.nextInt();
System.out.println("\nPlease enter the ending number:");
n2=input.nextInt();

System.out.print("\n     ");
    for (i1=1; i1<=10; i1++){

        System.out.print("    "+i1);
    }
    for (n1=n1; n1<=n2; n1++ ){
        System.out.print("\n    "+n1);

        for (i2=1; i2<=10; i2++){
            n3=n1*i2;
            System.out.print("    "+n3);

        }
    }
}
}

这是输出：

Please enter the starting number:
2

Please enter the ending number:
4

         1    2    3    4    5    6    7    8    9    10
    2    2    4    6    8    10    12    14    16    18    20
    3    3    6    9    12    15    18    21    24    27    30
    4    4    8    12    16    20    24    28    32    36    40

一旦有一个具有 2 个有效数字的整数，间距就会变得混乱。我该如何解决？谢谢！

Answer 1

通俗易懂的方式：如果小于10，打印一个额外的空格。

System.out.print("\n    ");
if(n1 < 10) System.out.print(" ");
System.out.print(n1);

更短的方法：String.format 可以用几种不同的方式格式化数字，其中一件事就是在开头自动添加空格：

System.out.println("\n    " + String.format("%2d", n1));
// alternatively:
System.out.println(String.format("\n    %2d", n1));

或者，System.out.printf 结合了 format 和 println 调用：

System.out.printf("\n    %2d", n1);

记得在打印i1和n3时做同样的事情！

Answer 2

http://www.tutorialspoint.com/compile_java_online.php

import java.util.Scanner;
public class HelloWorld{
public static void main(String []args){
    int n1,n2,n3;
    int i1, i2;
    char again;
    Scanner input=new Scanner(System.in);
    System.out.println("Please enter the starting number:");
    n1=input.nextInt();
    System.out.println("\nPlease enter the ending number:");
    n2=input.nextInt();
    System.out.print("\n     ");
    for (i1=1; i1<=10; i1++){   
        System.out.print(String.format("    %2d",i1));
    }
    for (n1=n1; n1<=n2; n1++ ){
        System.out.print("\n    "+n1);
        for (i2=1; i2<=10; i2++){
            n3=n1*i2;
            System.out.print(String.format("    %2d", n3));  
        }
    }
}
}

Answer 3

只要你想放一些空间就用\t ..试试下面的代码

  public static void main(String[] s) {
    int n1, n2, n3;
    int i1, i2;
    char again;
    Scanner input = new Scanner(System.in);

    System.out.println("Please enter the starting number:");
    n1 = input.nextInt();
    System.out.println("\nPlease enter the ending number:");
    n2 = input.nextInt();

    System.out.print("\n\t");
    for (i1 = 1; i1 <= 10; i1++) {

        System.out.print("\t" + i1);
    }
    for (n1 = n1; n1 <= n2; n1++) {
        System.out.print("\n\t" + n1);

        for (i2 = 1; i2 <= 10; i2++) {
            n3 = n1 * i2;
            System.out.print("\t" + n3);

        }
    }
 }

此代码输出将是

    1   2   3   4   5   6   7   8   9   10
1   1   2   3   4   5   6   7   8   9   10
2   2   4   6   8   10  12  14  16  18  20
3   3   6   9   12  15  18  21  24  27  30
4   4   8   12  16  20  24  28  32  36  40

Answer 4

import java.util.Scanner;
public class HelloWorld
{
public static void main (String args[])
{

int n1,n2,n3;
int i1, i2;
char again;
Scanner input=new Scanner(System.in);


System.out.println("Please enter the starting number:");
n1=input.nextInt();
System.out.println("\nPlease enter the ending number:");
n2=input.nextInt();

System.out.print("\n     ");
    for (i1=1; i1<=10; i1++){
        if(i1>9)
            System.out.print("   "+i1);
            else
        System.out.print("    "+i1);
    }
    for (n1=n1; n1<=n2; n1++ ){

        System.out.print("\n    "+n1);

        for (i2=1; i2<=10; i2++){
            n3=n1*i2;
            if(n3>9)
            System.out.print("   "+n3);
            else
            System.out.print("    "+n3);

        }
    }
}
}

这就是它应该的样子。只需删除一个空格，因为数字中有 2 个字符大于 9。因此，要以正确的方式对其进行格式化，您需要做的就是在打印时删除一个空格。