Patterns in C

All 17 patterns are re-corrected and verified

/*

Title : patterns in C

Author : Harshit, Edited by : Ashish

IDE : Code::Blocks v16.01

Date : 26 Feb 2017

*/

#include <stdio.h>

#include <conio.h>

void main(void)

    int i,j,k,l,input; //k & l if required further

    printf("enter no. of rows\n",input);// Enter no. of rows required

    scanf("%d",&input);

~~pattern will be written here~~

    getch();

~~//. . . these dots indicate length of the input so don't be confused the following patterns are for input = 4~~

/* pattern no: 1

1

1 2

1 2 3

1 2 3 4...

*/

    for(i = 1;i<=input;i++)

        for(j=1;j<=i;j++)

            printf("%d",j);

        printf("\n");

/* pattern no: 2

1

2 1

3 2 1

4 3 2 1

...

*/

     for(i = 1;i<=input;i++)

        for(j=i;j>0;j--) // j should be greater than 0 or >=1

            printf("%d",j);

        printf("\n");

/* pattern no: 3

1

2 2

3 3 3

4 4 4 4

...

*/

   for(i = 1;i<=input;i++)

        for(j=1;j<=i;j++)

         printf("%d",i);

        printf("\n");

/* pattern no: 4

1

2 3

4 5 6

7 8 9 10

...

*/

 k=0; // variable initiation

    for(i = 1;i<=input;i++)

        for(j=1;j<=i;j++)

        k++;

         printf("%d",k);

        printf("\n");

/* pattern no: 5

*

* *

* * *

* * * * . . .

*/

 for(i = 1;i<=input;i++)

        for(j=1;j<=i;j++)

         printf("* ");

        printf("\n");

/* pattern no: 6

* * * *...

* * *

* *

*

*/

  for(i = 1;i<=input;i++)

        for(j=input;j>=i;j--)

         printf("* ");

        printf("\n");

/* pattern no: 7

...4 3 2 1

...4 3 2

...4 3

...4

...

*/

 for(i = 1;i<=input;i++)

        for(j=input;j>=i;j--)

            printf("%d",j);

        printf("\n");

/* pattern no: 8

1

21

321

4321

...

*/

     for(i = 1;i<=input;i++)

        for(j=input;j>i;j--)

            printf(" ");

        for (k=i;k>0;k--)

        printf("%d",k);

    printf("\n");

/* pattern no: 9

1

12

123

1234

...

*/

 for(i = 1;i<=input;i++)

        for(j=input;j>i;j--)

            printf(" ");

        for (k=1;k<=i;k++)

        printf("%d",k);

    printf("\n");

/* pattern no: 10 tree of *

*

* *

* * *

* * * *

...

*/

     for(i = 1;i<=input;i++)

        for(j=input;j>i;j--)

            printf(" ");

        for (k=1;k<=i;k++)

        printf("*");

        for (l=2;l<=i;l++)// "l" must start from 2 bcoz for 1st row 1 "*" has               already printed in "k"

        printf("*");

    printf("\n");

/* pattern no: 11 Diamond (no. of rows be 2 x input-1)

*

* *

* * *

* * * *

* * *

* *

*

*/

     for(i = 1;i<=input;i++)

        for(j=input;j>i;j--)

            printf(" ");

        for (k=1;k<=i;k++)

        printf("*");

        for (l=2;l<=i;l++)

        printf("*");

    printf("\n");

      for(i = input-1;i>=1;i--)//here input must be one less bcoz one time input   has been printed now we have to invert it

        for(j=input;j>i;j--)

            printf(" ");

        for (k=1;k<=i;k++)

        printf("*");

        for (l=2;l<=i;l++)

        printf("*");

    printf("\n");

/* pattern no: 12

A

A B

A B C

A B C D . . . not valid after 26 rows

*/

  char ch='A';

 for(i = 1;i<=input;i++)

      for(j=1;j<=i;j++)

         printf("%c",ch);

         ch++;

        printf("\n");

    ch='A';

/* pattern no: 13

A

B C

D E F

G H I J

. . . not valid after 7 rows

*/

  char ch='A';

 for(i = 1;i<=input;i++)

      for(j=1;j<=i;j++)

         printf("%c",ch);

         ch++;

        printf("\n");

/* pattern no: 14

A

B A

C B A

D C B A

. . . not valid after 26 rows

*/

 char ch='A';

 for(i = 1;i<=input;i++)

        for(j=input;j>i;j--)

            printf(" ");

        for (k=1;k<=i;k++)

        printf("%c",ch);

        ch++;

    printf("\n");

    ch='A';

/* pattern no: 15 (input = 4, max 7)

ABCDE

FGHI

JKL

MN

*/

  char ch='A';

for(i = 1;i<=input;i++)

        for(j=input;j>=i;j--)

            printf("%c",ch);

            ch++;

        printf("\n");

/* pattern no: 16 (input = 4, max 26)

...

ABCD

ABC

AB

A

*/

char ch='A';

for(i = 1;i<=input;i++) // or for(i = input;i>0;i--)

        for(j=input;j>=i;j--) // or for(j=1;j<=i;j++)

            printf("%c",ch);

            ch++;

        printf("\n");

        ch='A';

/* pattern no: 17 (input = 4, max 26)

...

Z Y X W

Z Y X

Z Y

Z

*/

//if you want different initialization then your input should be static not variable E.g: if ch='E'then input=5, if ch='F' then input=6 and so on.

char ch='Z';

 for(i = 1;i<=input;i++)

        for(j=input;j>=i;j--)

         printf("%c",ch);

         ch--;

        printf("\n");

        ch='Z';

pdf has some mistakes they are corrected above

patterns in c.pdf