Print matrix in snake pattern in C Programming.

In C programming, printing a matrix in snake pattern means traversing the matrix row by row where even-indexed rows are printed from left to right and odd-indexed rows are printed from right to left. This creates a snake-like zigzag pattern through the matrix elements.

Syntax

for (i = 0; i < rows; i++) {
    if (i % 2 == 0) {
        // Print left to right for even rows
        for (j = 0; j < cols; j++)
            printf("%d ", arr[i][j]);
    } else {
        // Print right to left for odd rows
        for (j = cols - 1; j >= 0; j--)
            printf("%d ", arr[i][j]);
    }
}

Algorithm

1. Initialize − Create a 2D array with elements
2. Iterate through rows − Use a loop from 0 to number of rows
3. Check row index − If row index is even (i % 2 == 0)
4. Print left to right − Traverse columns from 0 to N-1
5. Print right to left − For odd rows, traverse columns from N-1 to 0

Example

#include <stdio.h>
#define M 4
#define N 4

int main() {
    int i, j;
    int arr[M][N] = {
        { 100, 99, 98, 97 },
        { 93, 94, 95, 96 },
        { 92, 91, 90, 89 },
        { 85, 86, 87, 88 }
    };
    
    printf("Matrix in snake pattern: ");
    for (i = 0; i < M; i++) {
        if (i % 2 == 0) {
            // Even row: left to right
            for (j = 0; j < N; j++)
                printf("%d ", arr[i][j]);
        } else {
            // Odd row: right to left
            for (j = N - 1; j >= 0; j--)
                printf("%d ", arr[i][j]);
        }
    }
    printf("<br>");
    return 0;
}

Matrix in snake pattern: 100 99 98 97 96 95 94 93 92 91 90 89 88 87 86 85

Key Points

• Even-indexed rows (0, 2, 4...) are traversed from left to right
• Odd-indexed rows (1, 3, 5...) are traversed from right to left
• The pattern creates a continuous snake-like path through the matrix
• Time complexity is O(M × N) where M is rows and N is columns

Conclusion

The snake pattern traversal efficiently prints matrix elements in a zigzag manner by alternating the direction of traversal for each row. This technique is useful in matrix manipulation and spiral traversal problems.