How To Use C Programming To Make A Spiral Matrix

Introduction

A spiral matrix is two-dimensional. To create it, you fill the array with numbers in a spiral pattern. Starting at the top-left corner, the numbers move right, followed by down, left, and up. This process repeats until the matrix is completely filled.

Moreover, working on a spiral matrix helps you practice important C programming concepts. For instance, you’ll work with loops, conditionals, and matrix manipulation. As a result, this exercise deepens your understanding of how arrays and logic interact in C programming. Ultimately, you’ll strengthen your grasp of these core programming skills.

#include <stdio.h>

void generateSpiralMatrix(int n) {
    int matrix[n][n];
    int top = 0, bottom = n - 1, left = 0, right = n - 1;
    int value = 1;

    while (top <= bottom && left <= right) {
        // Fill top row (left to right)
        for (int i = left; i <= right; i++) {
            matrix[top][i] = value++;
        }
        top++;

        // Fill right column (top to bottom)
        for (int i = top; i <= bottom; i++) {
            matrix[i][right] = value++;
        }
        right--;

        // Fill bottom row (right to left)
        if (top <= bottom) {
            for (int i = right; i >= left; i--) {
                matrix[bottom][i] = value++;
            }
            bottom--;
        }

        // Fill left column (bottom to top)
        if (left <= right) {
            for (int i = bottom; i >= top; i--) {
                matrix[i][left] = value++;
            }
            left++;
        }
    }

    // Print the matrix
    printf("Spiral Matrix:\n");
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < n; j++) {
            printf("%d ", matrix[i][j]);
        }
        printf("\n");
    }
}

int main() {
    int n;
    printf("Enter the size of the matrix (n x n): ");
    scanf("%d", &n);
    generateSpiralMatrix(n);
    return 0;
}

Input

Enter the size of the matrix (n x n): 4

Output

Spiral Matrix:
1 2 3 4
12 13 14 5
11 16 15 6
10 9 8 7

Explanation

Matrix Initialization

First, we create a 2D matrix of size n×nn \times nn×n, where each element will be assigned a value in spiral order.

Spiral Logic:

• We use four variables (top, bottom, left, right) to track the boundaries of the matrix.
• The matrix is filled by traversing the edges in a spiral order:
  • First, we fill the top row (from left to right).
  • Then, the right column (from top to bottom).
  • After that, we fill the bottom row (from right to left).
  • Finally, we fill the left column (from bottom to top).
• This process repeats until all positions in the matrix are filled.

Value Increment: The variable value is incremented from 1 up to n2n^2n2 as we fill the matrix.

Output: After generating the matrix, the program prints the values in a neat grid format.

Conclusion

Creating a spiral matrix in C is an excellent exercise to improve your understanding of 2D arrays and loops. This algorithm efficiently fills the matrix in a spiral order and demonstrates how to control array boundaries dynamically. By modifying the size of the matrix and observing the output, you can practice handling dynamic data structures in C.