x64 vs x86 code example

Example 1: x86 and x64 meaning

Difference between x64 and x86. It usually refers to x86 for 32 bit OS and x64 for system with 64 bit. Technically x86 simply refers to a family of processors and the instruction set they all use. ... The 64 bit computers can run both 32bit programs and 64 bit programs

Example 2: what is i686 vs x86_64

i686 = 32-bit Intel x86 arch 
x86_64 = 64-bit Intel x86 arch