Answer 1

It's an integer array. You can only store int type in array "arr" there.
Arrays in c/c++/java are homogenious (same) type data structure.

Answer 2

Instead of Union, better to use structure.
and

vector of vector may works.
And ' variant '(as shown in above code by @lona), ' tuple ', classes may help in that case. But its some complex to understand now. (I think it's works only above c++11 only)

edit: Manav Roy

#include <iostream>

#include <tuple>
using namespace std;

struct st
{

int i;
string s;
double d;
};

int main()
{

cout<< "by using structure\n" :
st a = { 30, "abc", 12.5};

cout << "int " << a.i << "\nstring: " << a.s <<"\ndouble : "<<a.d<<'\n';

std::cout << "\nusing tuple\n\n";

tuple<int, string, double> t{ 30,"Abc",12.5 };

cout<< get<0>(t)<<"\n";
cout<< get<1>(t)<<"\n";
cout<< get<2>(t);

return 0;
}

Answer 3

Hi, you could try union or if using STL, then std::variant.

#include <iostream>
#include <variant>

union myDataType
{
int i;
char ch;
};

int main()
{
myDataType arr[4] = { 11, 20, 30, 40};
arr[2].ch = 'h';
for (const myDataType& i : arr)
{
std::cout << "int form: " << i.i << " char form: " << i.ch << '\n';
}
// STL c++17
std::cout << "using C++ 17\n\n";
std::variant<int, char> arr2[] = { 11, 20, 30, 40 };
arr2[2] = 'h';
for (const std::variant<int, char>& i : arr2)
{
if (std::holds_alternative<int>(i))
{
std::cout << "int form: " << std::get<0>(i) << '\n';
}
else
{
std::cout << "char form: " << std::get<1>(i) << '\n';
}
}
return 0;
}

Answer 4

In this case you can use struct that can include different types see Jayakrishna🇮🇳 answer