Alphabet Pattern 1

/*

 * C Program to print following pattern

 *

 *      A B C D E D C B A

 *        A B C D C B A

 *          A B C B A

 *            A B A

 *              A

 *

 */

// Include

#include <stdio.h>

// Declarations

/*

 * printPattern

 * Description : Function to print pattern provided in description.

 * Parameters  : int - number of lines to be printed for given pattern.

 * Return      : void

 */

void printPattern(int i_numberOfLines);

// Definitions

int main()

{

    int i_numberOfLines = 0;

    printf("How many lines would you like to print : ");

    scanf("%d",&i_numberOfLines);

    printPattern(i_numberOfLines);

    return 0;

}

void printPattern(int i_numberOfLines)

{

    register int row, spaces, letters, noOfLetters;

    // Loop to repeat for each row

    for (row = 1; row <= i_numberOfLines; row++)

    {

        // Loop for printing spaces

        // Observe that spaces are incremental on each line.

        // row 1=0, row 2 = 1, row 3 =2 and so on.

        // So essentially number of spaces on each row is 1 less that current row.

        for (spaces = 1; spaces < row; spaces++)

        {

            printf("  ");

        }

        

        // Loop for printing incremental letters A B C D E

        // Observe that number of incremental letters are less on each row.

        // row 1 = 5, row 2 = 4, row 3 = 3 and so on.

        // So number of incremental letters on row n = Total lines - current row + 1

        noOfLetters = i_numberOfLines - row + 1;

        for (letters = 0; letters < noOfLetters; letters++)

        {

            printf("%c ", 'A'+letters);

        }

        

        // Loop for printing decremental letters D C B A

        // Observer that number of decremental letters are less on each row.

        // row 1 = 4, row 2 = 3, row 3  = 2 and so on

        // So number of decremental letters on row n = Total lines - current row.

        noOfLetters = i_numberOfLines - row;

        for (letters = noOfLetters; letters>0; letters--)

        {

            printf("%c ",'A'+letters -1);

        }

        

        // Move on to next line

        printf("\n");

    }

}