How do I design an int loop that starts with 1 and ends with 0 (1,2,3,4,5,6,7,8,9,0)

Question

My problem is to use nested for loops in order to create this output:

         |         |         |         |         |         |
123456789012345678901234567890123456789012345678901234567890

I can't figure out the best way to replace the int 10 with 0. I've tried a few ways, but they are gimmicky, and don't seem right to me. I hope my problem is apparent, it's kind of hard to explain. Can someone point me in the right direction?

I've achieved the correct output, but something tells me that there is a better way to go about this. Here's my code:

int k = 0;  
for (int i=1; i<=6; i++){
   System.out.print("         |");
}
System.out.println();
for (int m=0; m<6; m++){
   for (int j=1; j<10; j++){
      System.out.print(j);
   }
   System.out.print(k);
}

Great! Modulo was the answer I was looking for. I feel much more comfortable with this:

for (int i=1;i<=6;i++){
   System.out.print("         |");
}
System.out.println();
for (int m=0;m<6;m++){
   for (int j=1;j<=10;j++){
      System.out.print(j % 10);
   }
}

Adam · Accepted Answer · 2010-12-09T23:19:18.850

11

Use the modulo operator %. It gives you the remainder. Therefore starting the loop at 1, when 1 is divided by 10 the remainder is 1. When 2 is divided by 10 the remainder is 2, etc.. When 10 is divided by 10 the output is 0.

for(int i = 1; i <= 10; i ++) {
      System.out.println(i % 10);
}

edited Dec 09 '10 at 23:19

answered Dec 09 '10 at 23:06

Adam

43,763
16
104
144

score 10 · Answer 2 · answered Dec 09 '10 at 23:04

10

You want the mod operator (%).

10 % 10 = 0
11 % 10 = 1

It calculates the remainder after division.

answered Dec 09 '10 at 23:04

Noon Silk

54,084
6
88
105

score 8 · Answer 3 · answered Dec 09 '10 at 23:05

8

Why can't you just generate this:

012345678901234567890123456789012345678901234567890123456789

And then take the character off the front and stick it on the end?

answered Dec 09 '10 at 23:05

Anon.

58,739
8
81
86

score 3 · Answer 4 · answered Dec 09 '10 at 23:05

There are many ways. The simplest is this, probably:

for (int i = 1; i <= 10; i++) {
   System.out.println(i % 10);
}

If you have 2 loops, then you can use this fact:

for (int i = 0; i < 5; i++) {
   for (int j = 1; j <= 9; j++) {
       System.out.print(j);
   }
   System.out.print(0);
}

ArBR · Answer 5 · 2015-03-29T04:23:01.747

2

If this represents a kind of pattern, then while not simply define the pattern and then output the result to the screen (or do whatever you want), it is:

printPattern("         |", 6);
printPattern("1234567890", 6);

public void printPattern(string pattern, int max)
{   
    int i = 0; 
    while (++i <= max)
        System.out.print(pattern);
    System.out.println();
}

edited Mar 29 '15 at 04:23

answered Dec 10 '10 at 01:04

ArBR

4,032
2
23
29

+1 Although output would suggest loop+modulus there's nothing wrong with keeping it simple! – Robben_Ford_Fan_boy Dec 10 '10 at 01:44

score 0 · Answer 6 · edited Aug 17 '12 at 16:46

0

You could try using modulo:

i = i % 10

edited Aug 17 '12 at 16:46

Conner

30,144
8
52
73

answered Dec 09 '10 at 23:05

Matthieu

16,103
10
59
86

score 0 · Answer 7 · answered Dec 09 '10 at 23:07

0

for (int i=1; i<100; i++)
    System.out.println(i%10);

answered Dec 09 '10 at 23:07

John

660
10
26

score 0 · Answer 8 · answered Dec 09 '10 at 23:12

0

Here's a non-modulo solution:

$x = 1;
while(1){
  if($x>9){
     $x=0;
  }
print $x;
$x++;
}

Yea, yea, I know it's cheap. It'll work though. ;)

answered Dec 09 '10 at 23:12

Satanicpuppy

1,569
8
11

@Software Monkey: I worried about that until I noticed that everyone elses did too. Or it only looped once. – Satanicpuppy Dec 10 '10 at 03:01

How do I design an int loop that starts with 1 and ends with 0 (1,2,3,4,5,6,7,8,9,0)

8 Answers8