If the highest sign bit is used, negative numbers will appear in C language.
Use sizeof (type) to determine the range.
Sizeof(int) equals 4, which means 4 * 8 = 32 bits 2 32 = 4294967296.
The range of int is-2147483647 ~ 2147483648.
Sizeof(int) is equal to 2, which means 2 * 8 = 16 bit 2 32 = 65536.
The range of int is -32768~32768.
The same type has different sizes in different compilers ~ ~