rotate matrix

t14e12.rotate.cpp

// t14e12.rotate.cpp
// juanfc 2025-11-04
// https://gist.github.com/juanfal/66dafa705d5fac43f1672315047d1d63

#include <iostream>
#include <iomanip>
#include <array>
using namespace std;

const int MAX = 5;
typedef array<array<int,MAX>,MAX> TSqMat;

int main()
{
    void print(TSqMat);
    void clockwise(TSqMat& m);
    void counterClockwise(TSqMat& m);

    TSqMat m = {{
        {{ 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}}
    }};
    TSqMat copy = m;
    cout << "orig:" << endl;
    print(m);
    clockwise(m);
    cout << "orig clockwise:" << endl;
    print(m);
    m = copy;
    counterClockwise(m);
    cout << "orig counterClockwise:" << endl;
    print(m);
    clockwise(m);
    cout << "orig counterClockwise + clockwise:" << endl;
    print(m);


    return 0;
}

void counterClockwise(TSqMat& m)
{
    void transpose(TSqMat&);
    void invertCols(TSqMat&);

    transpose(m);
    invertCols(m);
}

void clockwise(TSqMat& m)
{
    void transpose(TSqMat&);
    void invertRows(TSqMat&);

    transpose(m);
    invertRows(m);
}

void transpose(TSqMat& m)
{
    void swap(int&, int&);

    for (int row = 0; row < MAX; ++row)
        for (int col = row+1; col < MAX; ++col)
            swap(m[row][col], m[col][row]);
}

void invertCols(TSqMat& m)
{
    void swap(int&, int&);

    for (int row = 0; row < MAX/2; ++row)
        for (int col = 0; col < MAX; ++col)
            swap(m[row][col], m[MAX-1-row][col]);
}

void invertRows(TSqMat& m)
{
    void swap(int&, int&);

    for (int row = 0; row < MAX; ++row)
        for (int col = 0; col < MAX/2; ++col)
            swap(m[row][col], m[row][MAX-1-col]);
}


void print(TSqMat m)
{
    for (int i = 0; i < MAX; ++i) {
        for (int j = 0; j < MAX; ++j)
            cout << setw(4) << m[i][j];
        cout << endl;
    }
}

void swap(int& a, int& b)
{
    int t=a;a=b;b=t;
}