8. Multi-dimensional Arrays

8.1 Two-Dimensional Arrays

8.1.1 Declaration and Initialization

// Declaration
int matrix[3][4];  // 3 rows, 4 columns

// Initialization methods
int grid[2][3] = {
    {1, 2, 3},
    {4, 5, 6}
};

// Alternative initialization
int numbers[2][3] = {{1, 2, 3}, {4, 5, 6}};

// Partial initialization
int scores[3][2] = {
    {95, 87},
    {92, 78},
    {88}      // Last element becomes 0
};

8.1.2 Accessing 2D Array Elements

int matrix[3][4] = {
    {1,  2,  3,  4},
    {5,  6,  7,  8},
    {9, 10, 11, 12}
};

// Accessing elements
printf("Element at row 1, column 2: %d\n", matrix[1][2]);  // Output: 7

// Modifying elements
matrix[0][0] = 100;
matrix[2][3] = 999;

8.1.3 Input/Output for 2D Arrays

#include <stdio.h>

void input_matrix(int matrix[][4], int rows) {
    printf("Enter matrix elements:\n");
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < 4; j++) {
            printf("Element [%d][%d]: ", i, j);
            scanf("%d", &matrix[i][j]);
        }
    }
}

void print_matrix (int matrix[][4], int rows) {
    printf("Matrix:\n");
    for (int i = 0; i < rows; i++) {
        for (int j = 0; j < 4; j++) {
            printf("%d ", matrix[i][j]);
        }
        printf("\n");
    }
}