#include #include int main() { // Declare and initialize the matrix dimensions, // then indexes used for the spiral, and our // current direction. int n, m, j = 0, k = 0; enum {down, right, up, left} d = down; std::cout << "Enter the row and column size: " << std::flush; std::cin >> n >> m; std::cout << std::endl; // Verify the matrix dimensions are reasonable and if not // default them. if (n < 0 || n > 30) n = 5; if (m < 0 || m > 30) m = 5; // Declare and initialize array. int ary[30][30]; for (int i = 0; i < n; i++) for (int j = 0; j < m; j++) ary[i][j] = 0; // For the number of cells in the matrix, store the // value and figure out the next cell. for (int i = 1; i <= n*m; i++) { // Store the current number into the current cell. ary[j][k] = i; // If we are heading down and haven't reached the // column end or an already filled in cell, the // next cell is down one. Otherwise, change // direction to right. if (d == down) if (j < n-1 && ary[j+1][k] == 0) j++; else d = right; // If we are heading right and haven't reached the // row end or an already filled in cell, the // next cell is right one. Otherwise, change // direction to up. if (d == right) if (k < m-1 && ary[j][k+1] == 0) k++; else d = up; // If we are heading up and haven't reached the // column start or an already filled in cell, the // next cell is up one. Otherwise, change // direction to left. if (d == up) if (j > 0 && ary[j-1][k] == 0) j--; else d = left; // If we are heading left and haven't reached the // row start or an already filled in cell, the // next cell is left one. Otherwise, change // direction to down and the next cell is down // one. if (d == left) if (k > 0 && ary[j][k-1] == 0) k--; else { d = down; j++; } } // Output the matrix. for (int i = 0; i < n; i++) { for (int j = 0; j < m; j++) std::cout << std::setw(4) << ary[i][j]; std::cout << std::endl; } return 0; }

spiral mn