matrix_sort.cpp

#include <iostream>
#include <ctime>
using namespace std;

//matrix[i][j] == matrix[ j*N + i ] => pointer arithmetic

void random_matrix( int* matrix, int N ){
    srand(time(NULL));
    for ( int i = 0; i < N; i++ ){
        for ( int j = 0; j < N; j++ ){
            matrix[j*N+i] = rand()%10;
        }
    }
}

void print_matrix( int* matrix, int N ){
    for ( int i = 0; i < N; i++ ){
        for ( int j = 0; j < N; j++ ){
            cout << matrix[j*N+i];
        }
        cout << endl;
    }
}

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

void matrix_sort( int* matrix, int N ){
    //Bubble sort analogue
    bool swapped;
    do{
        swapped = 0;
        for ( int i = N-1; i >= 0; i-- ){
            for ( int j = N-1; j >= 0; j-- ){
                if ( i-1 >= 0 && matrix[j*N+i] < matrix[j*N+i-1] ){
                    swap( matrix[j*N+i], matrix[j*N+i-1] );
                    swapped = 1;
                }
                if ( j-1 >= 0 && matrix[j*N+i] < matrix[j*N-N+i] ){
                    swap( matrix[j*N+i], matrix[j*N-N+i] );
                    swapped = 1;
                }
            }
        }
    }while ( swapped );
}

int main(){
    int matrix[6][6] = {0};

    //sorts random 6x6 matrix
    random_matrix(&matrix[0][0], 6);
    print_matrix(&matrix[0][0], 6);
    matrix_sort(&matrix[0][0], 6);
    cout << endl;
    print_matrix(&matrix[0][0], 6);
    return 0;
}