Double data stored in char array returns a float value

Question

Why is it that when I store the DATA of a double value in a char array if I get the data from the char array to another double, it returns a Float value?

In this:

double vals = 3.141592654;
char xvals[sizeof(vals)];
memcpy(&xvals, &vals, sizeof(xvals));

double y;
memcpy(&y, &xvals, sizeof(xvals));
std::cout<<y<<"\n";

OUTPUT: 3.14159

Answer 1

It does not "return a float value" : std::cout will simply not print all those digits by default.

you can use std::setprecison (from <iomanip>) to change the number of digits to be printed :

#include <iostream>
#include <iomanip>

int main()
{
    double vals = 3.141592654;
    std::cout << vals << "\n";

    std::cout << std::setprecision(10);
    std::cout << vals;
    return 0;
}

Output:

3.14159

3.141592654

Answer 2

There has been no data loss or forced conversion. The default precision for cout is 6. This will give you the answer you need

std::cout<<std::setprecision(10)<<y<<"\n";

EDIT : You need to include the header <iomanip> for std::setprecision.