Multidimensional Arrays

The array we used in the last example was a one dimensional array. Arrays can have more than one dimension, these arrays-of-arrays are called multidimensional arrays. They are very similar to standard arrays with the exception that they have multiple sets of square brackets after the array identifier. A two dimensional array can be though of as a grid of rows and columns.

#include <stdio.h> const int num_rows = 7; const int num_columns = 5; int main() { int box[num_rows][num_columns]; int row, column; for(row = 0; row < num_rows; row++) for(column = 0; column < num_columns; column++) box[row][column] = column + (row * num_columns); for(row = 0; row < num_rows; row++) { for(column = 0; column < num_columns; column++) { printf("%4d", box[row][column]); } printf("\n"); } return 0; }

This will produce following result:

0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

The above array has two dimensions and can be called a doubly subscripted array. GCC allows arrays of up to 29 dimensions although actually using an array of more than three dimensions is very rare.