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c++gccdoubleunsigned-integer

Turning an unsigned integer into a double from 0 to 1. Dividing by integer limit not working

So I'm wanting to turn an unsigned integer (Fairly large one, often above half of the unsigned integer limit) into a double that shows how far it is between 0 and the unsigned integer limit. Problem is, dividing it by the unsigned integer limit is always returning 0. Example:

#include <iostream>
;
int main()
{
    uint64_t a = 11446744073709551615
    double b = a / 18446744073709551615;
    std::cout << b;
};

This always returns 0. Is there an alternative method or a way to fix this one? If it means anything, I'm using GCC with the -O3 optimisation flag.

Solution

  • You have to convert the expression on the right to double, for example, like this:

    double b = static_cast<double>(a) / 18446744073709551615;

    or

    double b = a / 18446744073709551615.0;