Print a text pattern in java

Question

I need the pattern to be printed in the form

   ABCDEF FEDCBA
   ABCDE   EDCBA
   ABCD     DCBA
   ABC       CBA
   AB         BA
   A           A

Below is my code :

   public static void main(String args[])
{
    char[] c = {'A','B','C','D','E','F','G'};
    int i, j;

    for(j = 5; j >= 0; j--)
    {
        for(int k = 0; k <= j; k++)
        {
            System.out.print(c[k]);
        }
        for(i = j; i >= 0; i--)
        {
            System.out.print(c[i]);
        }

        System.out.println();
    }
}

Which gives me the output as

   ABCDEFFEDCBA
   ABCDEEDCBA
   ABCDDCBA
   ABCCBA
   ABBA
   AA

It was fairly easy to reach to this output. However, i haven't been able to provide spaces. I know the loop to produce the space will come in between both the for loops but i couldn't figure out how to do it. Its bugging me for a while.

Answer 1

I give you hint, count the spaces :

For line 1 : 1 spaces

For line 2 : 3 spaces

For line 3 : 5 spaces

For line 4 : 7 spaces

etc., see the pattern? :)

And yes, put one more "space for cycle" between existing for cycles.

---

Spoiler ALERT, here is Java solution, but try to do it without it.

This is fully working code, it also works with any size of array :

public static void main(String args[]) {
    char[] c = {'A', 'B', 'C', 'D', 'E', 'F', 'G', 'Y', 'Z'};
    int i, j;

    for (j = c.length-1; j >= 0; j--) {
        for (int k = 0; k <= j; k++) {
            System.out.print(c[k]);
        }
        for (int k = 0; k < (c.length-j)*2 - 1; k++) {
            System.out.print(" ");
        }
        for (i = j; i >= 0; i--) {
            System.out.print(c[i]);
        }

        System.out.println();
    }
}

Sample output :

ABCDEFGYZ ZYGFEDCBA
ABCDEFGY   YGFEDCBA
ABCDEFG     GFEDCBA
ABCDEF       FEDCBA
ABCDE         EDCBA
ABCD           DCBA
ABC             CBA
AB               BA
A                 A

Answer 2

char[] c = {'A','B','C','D','E','F','G'};
    int i, j,n,p=1;

    for(j = 5; j >= 0; j--)
    {
        for(int k = 0; k <= j; k++)
        {
            System.out.print(c[k]);
        }
        for(n = 1; n <= p; n++)
        System.out.print(" ");
        p+=2;
        for(i = j; i >= 0; i--)
        {
            System.out.print(c[i]);
        }

        System.out.println();
    }

Answer 3

Even though there are some (already) answered solutions, too many loops increase the complexity:

char[] c = { 'A', 'B', 'C', 'D', 'E', 'F', 'G' };

for (int i = 0; i < c.length; i++) {
  String tmp = String.valueOf(c).substring(0, c.length - i);

  System.out.printf("%s %" + (c.length + i) + "s%n", tmp, new StringBuilder(tmp).reverse());
}

OUTPUT

ABCDEFG GFEDCBA
ABCDEF   FEDCBA
ABCDE     EDCBA
ABCD       DCBA
ABC         CBA
AB           BA
A             A

Your char array can be increased any time, the output would be "the same" (in terms of formatting).

Answer 4

Each row of your pattern is of fixed width: 13 characters. That means that if you print j characters (index of your outer loop), you need to print 13-2*j spaces.

for (int k=0; k<13-2*j; k++){
    System.out.print(" ");
}

Answer 5

Here I use a new variable max to set up j initially. This variable is used for the len calculation for the spaces.

char[] c = {'A','B','C','D','E','F','G'};
int i, j;

int max = 5; //your max output (could be 6)
for(j = max; j >= 0; j--)
{
    for(int k = 0; k <= j; k++)
    {
        System.out.print(c[k]);
    }
    int len = max*2+1; //length calculation
    for(int x = 0; x < len-2*j; x++){ //space loop
        System.out.print(" ");
    }
    for(i = j; i >= 0; i--)
    {
        System.out.print(c[i]);
    }

    System.out.println();
}

Answer 6

Please use proper names for your variables. Java is not Basic, so you can use up to 65,535 characters in a variable name if you wish.

Documentation through code helps people who have to maintain code in the future.

public class PrintChars {
  public static void main(String args[]) {
    char[] chars = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H' };
    int length = chars.length;

    for (int row = length; row > 0; row--) {
      for (int left = 0; left < row; left++) {
        System.out.print(chars[left]);
      }
      for (int space = 0; space < (length-row)*2+1; space++) {
        System.out.print(' ');
      }
      for (int right = row-1; right >= 0; right--) {
        System.out.print(chars[right]);
      }
      System.out.println();
    }
  }
}

Output:

ABCDEFGH HGFEDCBA
ABCDEFG   GFEDCBA
ABCDEF     FEDCBA
ABCDE       EDCBA
ABCD         DCBA
ABC           CBA
AB             BA
A               A