First of all, let me say that the plastic data mentioned in the book is in the past, and the range represented by 8-digit and signed numbers is-128~ 127. The unsigned number represents 0~255, and the computer we are using now is 32-bit, which means that the type of int you define is 32-bit, which is much larger than 256. When you define a=300, its cardinality of 16 should be 00000 12C, while in memory it is 2C0 10000 (small mantissa), so you use printf ("%c ",when c 1). ..