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This article mainly introduces "what is the way of data storage in C language". In daily operation, I believe that many people have doubts about what the way of data storage in C language is. The editor consulted all kinds of materials and sorted out simple and easy-to-use operation methods. I hope it will be helpful for you to answer the question of "what is the way of data storage in C language?" Next, please follow the editor to study!

I. Source code

The original code of a number (the original binary code) has the following characteristics:

The highest bit is the symbol bit, with 0 for positive and 1 for negative

The rest of the numerical value is the binary number of the absolute value of the numerical value itself.

The source code of a negative number is based on its absolute value, and the highest bit becomes 1.

The following values are described in 1 byte size:

Decimal number

Original code

+ 15

0000 1111

-15

1000 1111

+ 0

0000 0000

-0

1000 0000

Note: the representation of the original code is easy to understand, and it is convenient to convert with the signed number itself, as long as the symbol is restored, but when two positive numbers are subtracted or different symbolic numbers are added, it is necessary to compare which absolute value of the two numbers is larger in order to determine which one is positive or negative, so the original code is not convenient for addition and subtraction.

Second, inverse code

For positive numbers, the inverse code is the same as the original code

For negative numbers, the symbol bits remain unchanged, while the other parts are reversed (1 to 0, 0 to 1)

Decimal number

Inverse code

+ 15

0000 1111

-15

1111 0000

+ 0

0000 0000

-0

1111 1111

Note: inverse code operation is also inconvenient and is usually used as an intermediate transition for complementary codes.

Third, complement code

1. Complement description

In a computer system, values are always stored in complements.

Features of complement:

For positive numbers, the original code, inverse code and complement are the same.

For a negative number, its complement is added by its inverse code.

The complement symbol bit does not move, the other bits are inverted, and finally the whole number is added by 1 to get the original code.

Decimal number

Complement code

+ 15

0000 1111

-15

1111 0001

+ 0

0000 0000

-0

0000 0000

2. The meaning of complement

In computer systems, values are always stored in complements, mainly for the following reasons:

Unify the zero coding

Unify symbol bits with other bits

Transform subtraction into addition

When two numbers represented by complement are added together, if the highest bit (symbol bit) has carry, the carry is discarded.

Example: use 8-bit binary numbers to represent + 0 and-0, respectively

Decimal number

Original code

+ 0

0000 0000

-0

1000 0000

Decimal number

Inverse code

+ 0

0000 0000

-0

1111 1111

Note: no matter it is stored in the original code or in the inverse code, 0 also has two forms of representation. But if it is stored as a complement, the complement unifies the zero code:

Decimal number

Complement code

+ 0

0000 0000

-0

10000 0000 because only 8 bits are used, the highest bit 1 is discarded and becomes 0000 0000

IV. Case demonstration

Analog computer operation

1) 76-32

Computer algorithm: 76 + (- 32)

2) 76

Source code: 0100 1100

Inverse code: 0100 1100

Complement: 0100 1100

3)-32

Source code: 1010 0000

Inverse code: 1101 1111

Complement: 1110 0000

4) add

1110 0000

0100 1100

5) check calculation

Results: 1 0010 1100

Discard complement: 0010 1100

Result complement: 0010 1100

Inverse code: 0010 1100

Conversion source code: 0010 1100

Note: since the discard complement 0 is positive, the conversion source code is the same as the complement code.

6) results: 44

Note:

1. Positive number of symbol bits: 0

2. Negative number of symbol bits: 1

3. The result of complement calculation. If the symbol bit exceeds the size limit, the symbol bit will be omitted.

4. Complement result: the opening number is 1, it is converted to the source code according to the negative rule, and the first 0 is a positive conversion.

5. Positive numbers: source code, inverse code, complement code, same

6. Negative source code conversion code: the symbol remains unchanged, other bits 0 become 1, 1 become 0

7. Negative inverse code transcoding: add 1 to the result of the inverse code

8. The result of addition or subtraction cannot be greater than or less than negative 127.

At this point, the study of "what is the way to store data in C language" is over. I hope to be able to solve your doubts. The collocation of theory and practice can better help you learn, go and try it! If you want to continue to learn more related knowledge, please continue to follow the website, the editor will continue to work hard to bring you more practical articles!

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