[Super invincible and detailed Han Shunping's java notes] From beginner to proficient---Introduction to the four base systems

Introduction to base 1

For integers, there are four representations:
Binary: 0,1 , 2 to 1. Starts with 0b or 0B .
Decimal: 0-9 , 10 to 10 .
Octal: 0-7 , full 8- digit 1. It starts with the number 0 .
Hexadecimal: 0-9 and A(10)-F(15) , full hexadecimal 1. It starts with 0x or 0X . AF here is not case sensitive.
//演示四种进制
//
        public class BinaryTest {
            //编写一个 main 方法
        public static void main(String[] args) {
            //n1 二进制
    int n1 = 0b1010;
            //n2 10 进制
    int n2 = 1010;
            //n3 8 进制
    int n3 = 01010;
            //n4 16 进制
    int n4 = 0X10101;
        System.out.println("n1=" + n1);
        System.out.println("n2=" + n2);
        System.out.println("n3=" + n3);
        System.out.println("n4=" + n4);
        System.out.println(0x23A);
    }
}

 Binary icon

 

 3. Base conversion ( basic skills )

Introduction to base 1 conversion

Group 1:
1) Binary to decimal

2) Octal to decimal

3) Hexadecimal to decimal

The second group:
1) Convert decimal to binary
Rule: Keep dividing the number by 2 until the quotient is 0 , and then reverse the remainder obtained at each step to obtain the corresponding binary number.
Case: Please convert 34 to binary = 0B00100010

 

2) Convert decimal to octal
Rule: Keep dividing the number by 8 until the quotient is 0 , and then reverse the remainder obtained at each step to obtain the corresponding octal number.
Case: Please convert 131 to octal => 0203

3) Decimal to hexadecimal
Rule: Keep dividing the number by 16 until the quotient is 0 , and then reverse the remainder obtained at each step to obtain the corresponding hexadecimal number.
Case: Please convert 237 to hexadecimal => 0xED

 

The third group
1) Binary to octal
Rule: Starting from the low bit , convert every three digits of the binary number into the corresponding octal number.
Case: Please convert ob11010101 into octal
ob11(3)010(2)101(5) => 0325
2) Binary to hexadecimal
Rule: Starting from the low-order bit, convert the binary number into a corresponding hexadecimal number in groups of four digits .
Case: Please convert ob11010101 into hexadecimal
ob1101(D)0101(5) = 0xD5
Group 4
1) Octal to binary
Rule: Convert each digit of the octal number into a corresponding 3-digit binary number .
Case: Please convert 0237 into binary
02(010)3(011)7(111) = 0b10011111
2) Hexadecimal to binary
Rule: Convert each digit of the hexadecimal number into a corresponding 4-digit binary number .
Case: Please convert 0x23B into binary
0x2(0010)3(0011)B(1011) = 0b001000111011

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Origin blog.csdn.net/qq_45206556/article/details/131935985