How to Create Alphabet O Pattern in C Programming

C program to Print  Alphabet  O star pattern 

Example 

#include <stdio.h>

int main()

{

    int a, b;

    int n = 7; // height and width of the O

    for (a = 0; a < n; a++)

{

        for (b = 0; b < n; b++)

{

            // Print * for the boundary of O

            if ((a == 0 || a == n-1) && (b > 0 && b < n-1)

|| (b == 0 || b == n-1) && (a > 0 && a < n-1))

                printf("*");

            else

                printf(" ");

       

}

        printf("\n");

    }

    return 0;

}

This C Program Print  pattern in the shape of the capital letter O using asterisks  "*"
Explain Program

Step :1

Variable Declaration

int a, b;
int n = 7; // height and width of the O

a and b are loop variables:
a is used to track rows
b is used to track columns
n = 7 sets both the height and width of the "O". So the output will be a 7x7 grid.

Step :2

Outer Loop – Controls Rows

for (a = 0; a < n; a++)

 loop Run from a = 0 to a = 6 (7 row total).
Each iteration represents  new row.

Step :3  

Inner Loop – Controls Columns

for (b = 0; b < n; b++)

This loop run for each column in the row.
 for each row, it prints 7 characters (b = 0 to b = 6).

Step :4

 Conditional Statement use

if ((a == 0 || a == n-1) && (b > 0 && b < n-1) 

 || (b == 0 || b == n-1) && (a > 0 && a < n-1))

    printf("*");

else

    printf(" ");

Let’s break this condition down:

Step :5

First Part: 

(a== 0 || a == n-1) && (b > 0 && b < n-1)

Handles top and bottom row, but only middle part
a == 0 → first row (top of the O)
a == n-1 → last row (bottom of the O)
b > 0 && b < n-1 → avoid the corners 

Step :6

This draws the top and bottom horizontal lines of the 'O' (excluding corners).
Second Part:

 (b == 0 || b == n-1) && (a > 0 && a < n-1)

handles the left and right column, but only the middle part

b == 0 → first column (left edge)
b == n-1 → last column (right edge)
a > 0 && a < n-1 → avoid the top and bottom rows

Step :7

This draws the left and right vertical lines of the 'O' (excluding corners).
 Else Case

    printf(" ");

 condition is not met, it prints a space, so the inside of the 'O' is hollow.

Step :8

printf("\n");

After each row is completed, move to  next line.

C program to Print  Alphabet  O star pattern 

Output

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