C++ make a variable type depend on user input

Question

I want a function that creates an array for testing purposes:

• The idea es to make the user select the type of elements the array will contain (int, float, doub

Answer 1

I think you should re-think your design.

Rather than trying to write a function that returns an array of user-defined type to test. I would instead call a different test function depending on the user choice.

The test function can be templated to avoid code duplication:

#include 
#include 

template
void doTest(unsigned size) {

    std::vector data(size);

    // Do the actual test on the data...
}


int main() {
    unsigned size;
    std::cout << "Size: \n";
    std::cin >> size;

    int op;
    std::cout << "Select type\n";
    std::cin >> op;
    switch(op) {
     case 0:
         doTest(size);
         break;
     case 1:
     default:
         doTest(size);
    }
}

If you really want to return your array from a function you could wrap it in a polymorphic type. But to actually do anything with the array you would need to call a virtual method on the polymorphic type so I don't see how it buys you anything over calling a test function directly.