Overview of computer system input System

1. Number: A method of representing numeric values using a set of fixed symbols and uniform rules.

2. The system used at the bottom of the computer is binary.

3.java programming uses a decimal. The binary that is still used in the Java bottom.

4. Computers are commonly used in binary, octal, decimal, hexadecimal.

(a): decimal

The basic number of decimal 0~9, every ten.

10 is called "cardinality", and 10^n (the power of 10 N) is called "right",

10000 = 1 * 104

1000 = 1 * 103

100 = 1 * 102

10 = 1 * 101

1 = 1 * 100

Example: 23678 (10 binary) = 2 * 10000 + 3 * 1000 + 6 * 100 + 7 * 10 + 8 * 1

=2*104 + 3*103 + 6*102 + 7*101 + 8*100

=23678

(ii) binary

The basic number of the binary is 0, 1, every 2.

The cardinality of the binary is 2, the right is 2^n (2 of the n-th square)

1 = 1*20

10 = 1*21

100 = 1*22

1000 = 1*23

10000 = 1*24

100000 = 1*25

1000000 = 1*26

10000000 = 1*27

Example: (1111) 2 = (___) 10

(1111) 2 = 1*23 + 1*22 + 1*21 + 1*20

= 8 + 4 + 2 + 1

= 15

(c) Hexadecimal

1.16 binary is a shorthand for binary, which facilitates writing binary data for professionals.

2. Basic number of 16 binary: 0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f (a=10,b=11,c=12,d=13,e=14,f=15)

3. The 16 binary is the Radix 16, the right is 16^n (16 of the n-th square)

4. Features: every 16

The hexadecimal number in the 5.Java code is prefixed with 0X or 0x (0 is the array 0, not the letter O)

0X1000 = 1*163

0X100 = 1*162

0X10 = 1*161

0x1 = 1*160

Example: (5E) 16 = (___) 10

= 5*161 + 14*160

= 80 + 14

= 94

Overview of computer system input System