Создание матрицы с динамическими размерами

void createMatrix() {
int first[3], second[3], third[3];
 
cout<<"first Line \n";
cin>> first[0]>>first[1]>>first[2];
cout<<"second Line \n";
cin>> second[0]>>second[1]>>second[2];
cout<<"third Line \n";
cin>> third[0]>>third[1]>>third[2];
 
int primary[3][3] = {first,second,third} ;// тут выдает ошибку
cout<<primary[1][0];
 
}

int primary[3][3];
 
cout<<"first Line \n";
cin>> primary[0][0]>>primary[0][1]>>primary[0][2];
cout<<"second Line \n";
cin>> primary[1][0]>>primary[1][1]>>primary[1][2];
cout<<"third Line \n";
cin>> primary[2][0]>>primary[2][1]>>primary[2][2];

string result = primary[0][0]+" "+primary[0][1]+" "+primary[0][2];

#include <sstream>
#include <iostream>
#include <string>
 
int main()
{
    int arr1[]{1,2,3}, arr2[]{4,5,6};
    int* matrix[]{arr1, arr2};
    std::stringstream ss;
    ss << matrix[0][0] << "  " << matrix[0][1] << "  " << matrix[0][2];
    std::string s(ss.str());
    std::cout << s << std::endl;
    return 0;
}

#include<iostream.h>
#include<conio.h>
#pragma argsused
 
int Show(int line, int columns,bool show, int primary[]) {
 
for (int i = 0; i < 2;i++) {
 
for (int j = 0; j< 4;j++) {
 
if (!show){
cin>>primary[i][j]; // выдает тут ошибку
} else {
cout<< primary[i][j];
}
 
}
 cout<<"\n";
}
return  primary;
}
 
 
void createMatrix() {
 
int line = 2;
int columns = 4;
int primary[line][columns];
 
 primary = Show(line, columns, false,primary);
 Show(line, columns, true,primary);
 
}
 
int main(int argc, char* argv[])
{
 
 createMatrix();
 getch();
        return 0;
}

[C++ Error] Unit1.cpp(18): E2062 Invalid indirection
[C++ Error] Unit1.cpp(20): E2062 Invalid indirection
[C++ Error] Unit1.cpp(26): E2034 Cannot convert 'int *' to 'int'
[C++ Error] Unit1.cpp(36): E2034 Cannot convert 'int ( *)[4]' to 'int *'
[C++ Error] Unit1.cpp(36): E2342 Type mismatch in parameter 'primary' (wanted 'int *', got 'int ( *)[4]')
[C++ Error] Unit1.cpp(36): E2277 Lvalue required
[C++ Error] Unit1.cpp(37): E2034 Cannot convert 'int ( *)[4]' to 'int *'
[C++ Error] Unit1.cpp(37): E2342 Type mismatch in parameter 'primary' (wanted 'int *', got 'int ( *)[4]')