1.6 Given an image represented by an NxN matrix, where each pixel in the image is 4 bytes, write a method to rotate the image by 90 degrees. Can you do this in place?

1.6.cpp

#include<iostream>

using namespace std;

const int N = 4;

void rotate(int matrix[][N])
{
    for (int i = 0; i < N/2; i++) {
        for (int j = i; j < N-1-i; j++) {
            int temp = matrix[i][j];
            matrix[i][j] = matrix[N-1-j][i];
            matrix[N-1-j][i] = matrix[N-1-i][N-1-j];
            matrix[N-1-i][N-1-j] = matrix[j][N-1-i];
            matrix[j][N-1-i] = temp;
        }
    }
}

void rotate0(int matrix[][N])
{
    for (int layer = 0; layer < N/2; layer++) {
        int first = layer;
        int last = N-1-layer;
        for (int i = first; i < last; i++) {
            int offset = i - first;
            // save top
            int top = matrix[first][i];
            // left -> top
            matrix[first][i] = matrix[last-offset][first];
            // bottom -> left
            matrix[last-offset][first] = matrix[last][last-offset];
            // right -> bottom
            matrix[last][last-offset] = matrix[i][last];
            // top -> right
            matrix[i][last] = top;
        }
    }
}

void print(int matrix[][N])
{
    for (int nRow = 0; nRow < N; nRow++)
    {
        for (int nCol = 0; nCol < N; nCol++)
            cout << matrix[nRow][nCol] << "\t";
        
        cout << endl;
    }
}

int main(int argc, char *argv[])
{
    int m[][N]{{1,2,3,4},{5,6,7,8},{9,10,11,12},{13,14,15,16}};
    print(m);
    cout << endl;
    rotate(m);
    print(m);
    return 0;
}