The reason is because those numbers are stored on your computer as finite binary numbers called floating point numbers, and they cannot represent exactly those values:
- in just the same way that you cannot write 1/3 exactly using a finite decimal fraction,
- and pi cannot be written with a finite number of digits in any integer base...
Your code tests for equivalence of floating point numbers, which is always unreliable. You need to change your algorithm to take into account floating point error:
etc, etc, etc
