How do I use bitwise operators on a “double” on C++?

Question

I was asked to get the internal binary representation of different types in C. My program currently works fine with \'int\' but I would like to use it with \"double\" and \"

Answer 1

As others have said, you can use a bitwise operator on a double by casting double* to long long* (or sometimes just long*).

int main(){
    double * x = (double*)malloc(sizeof(double));
    *x = -5.12345;
    printf("%f\n", *x);
    *((long*)x) &= 0x7FFFFFFFFFFFFFFF;
    printf("%f\n", *x);
    return 0;
}

On my computer, this code prints:

-5.123450
5.123450