90 degree clockwise matrix rotation.

rotate.d

import std.stdio;

auto rotate(T)(T[][] array) {
	foreach(i; 0 .. array.length/2) {
		foreach(j; i .. array.length-i-1) {
			T temp = array[i][j];
			array[i][j] = array[array.length-j-1][i];
			array[array.length-j-1][i] = array[array.length-i-1][array.length-j-1];
			array[array.length-i-1][array.length-j-1] = array[j][array.length-i-1];
			array[j][array.length-i-1] = temp;
		}
	}
}

void printArray(T)(T[][] array) {
	foreach (subarray; array) {
		writeln(subarray);
	}
}

void main() {
	int[][] array = [
		[1,2,3,4,5],
		[2,4,6,8,10],
		[1,3,5,7,9],
		[2,3,5,7,11],
		[9,8,7,6,5]
	];
	rotate(array);
	printArray(array);
}