issue with rolling mean

[ghost]

Hi All,
This is reiteration of the old stackoverflow question. Rolling mean seems not working correctly with unsigned integers. My system: Mac OS, High Sierra, the latest brew updates.

// g++ -std=c++11 -o accum_test accum_test.cpp
Sample file is attached.
accum_test.txt

OUTPUT:

***** Signed integers *****
9 actualMean: 9.0000000000000000
8 actualMean: 8.5000000000000000
7 actualMean: 8.0000000000000000
5 actualMean: 7.2500000000000000
6 actualMean: 7.0000000000000000
4 actualMean: 6.0000000000000000
3 actualMean: 5.0000000000000000
2 actualMean: 4.0000000000000000
1 actualMean: 3.2000000000000002
0 actualMean: 2.0000000000000000
0 actualMean: 1.2000000000000000
0 actualMean: 0.6000000000000000
0 actualMean: 0.2000000000000000
0 actualMean: -0.0000000000000001
0 actualMean: -0.0000000000000001
0 actualMean: -0.0000000000000001

***** Unsigned integers *****
9 actualMean: 9.0000000000000000
8 actualMean: 8.5000000000000000
7 actualMean: 8.0000000000000000
5 actualMean: 7.2500000000000000
6 actualMean: 7.0000000000000000
4 actualMean: 858993465.2000000476837158
3 actualMean: 1717986923.4000000953674316
2 actualMean: 2576980381.6000003814697266
1 actualMean: 3435973840.0000004768371582
0 actualMean: 4294967298.0000000000000000
0 actualMean: 5153960756.3999996185302734
0 actualMean: 6012954215.0000000000000000
0 actualMean: 6871947673.8000001907348633
0 actualMean: 7730941132.8000001907348633
0 actualMean: 7730941132.8000001907348633
0 actualMean: 7730941132.8000001907348633