C++ / Python: Why is 1==1.0 true? Why is 1==1.0000000000000001 true?

Question

From my understanding 1 is an integer type, while 1.0 and 1.0000000000000001 are floats.

C++:
#include <iostream>
using namespace std;

int main() {
cout<< bool(1==1.0); // outputs 1 (True)
return 0;
}

Python:
print(1==1.0000000000000001) # outputs True

Why are both of these evaluated as true?

Answer 1

for c++ the int gets converted to float before comparaison.
for print(1==1.0000000000000001)
on 64bit cpu the largest number of decimal digits you can use in a double is 15 and that number has 16 so the last digit 1 is omitted, so you get 1.0, remove one zero and you get a different number.