Sorting Matrix with qsort function C++ - c++

Question

Hello guys I need to know what should I pass to qsort function to make this work?
Everything else must stay as it is except arguments of qsort function.
#include <iostream>
#include <stdlib.h>
#include <math.h>
using namespace std;
void printMatrix(int **matrix, int n){
for(int i = 0; i<n; i++){
for(int j =0 ; j < n; j++)
cout<<matrix[i][j]<<" ";
cout<<endl;
}
}
void initMatrix(int **matrix, int n){
for(int i = 0; i<n; i++){
for(int j =0 ; j < n; j++){
matrix[i][j] = rand()%10;
}
}
}
int compar(const void *a, const void *b){
int ia = *((int*)a);
int ib = *((int*)b);
return ia-ib;
}
void deleteMatrix(int **matrix){
delete [] matrix;
}
int main()
{
cout<<"How many rows and cols?"<<endl;
int n;
cin>>n;
int **matrix;
matrix = new int* [n];
for(int j = 0; j < n; j++)
matrix[j] = new int[n];
initMatrix(matrix,n);
printMatrix(matrix,n);
cout<<"Sorted matrix:"<<endl;
qsort(matrix,n*n,sizeof(int),compar); //<-----------
printMatrix(matrix,n);
deleteMatrix(matrix);
return 0;
}
P.S
There must be ** pointer on matrix.
Thanks in advance!

Answer 1

You would probably be better off flattening the matrix to 1 dimension and using a step variable to determine where each row would start. Then sorting is easy.
#include <algorithm>
#include <iostream>
#include <stdlib.h>
#include <math.h>
using namespace std;
void printMatrix(int *matrix, int matrixsize, int rowsize) {
for (int i = 0; i < matrixsize; i+= rowsize)
{
for (int j = 0; j < rowsize; j++)
{
cout << matrix[i + j] << " ";
}
cout << endl;
}
}
void initMatrix(int *matrix, int n)
{
for (int i = 0; i < n; i++)
{
matrix[i] = rand() % 10;
}
}
void deleteMatrix(int *matrix) {
delete[] matrix;
}
int main()
{
cout << "How many rows and cols?" << endl;
int row;
cin >> row;
int matrixSize = row*row;
int *matrix = new int[matrixSize];
initMatrix(matrix, matrixSize);
printMatrix(matrix, matrixSize, row);
cout << "Sorted matrix:" << endl;
sort(matrix,matrix + matrixSize); //<-----------
printMatrix(matrix, matrixSize, row);
deleteMatrix(matrix);
return 0;
}