Values of int type require 32 bits (4 bytes) of memory. It means that there are 2³² different possible values of int variable. Half of them are positive and half are negative. Numbers with a higher-order bit equal to one are considered to be negative:

00000000 00000000 00000000 00000000₂ = 0₁₀
00000000 00000000 00000000 00000001₂ = 1₁₀
. . .
01111111 11111111 11111111 11111111₂ = 2147483647₁₀ = 2³¹–1
10000000 00000000 00000000 00000000₂ = –2147483648₁₀ = –2³¹
. . .
11111111 11111111 11111111 11111111₂ = –1₁₀

Therefore, in the process of a loop execution a -2147483648 number will follow after a 2147483647 number. Since it does not satisfy the cycle continuation condition, program will exit the loop.