12th Chapter Fundamental Data Types Basic datatype

Catalog: 12.1 Numerical Introduction

12.2 integers

12.3 floating Point

12.4 Characters and strings

12.5 Boolean variables

12.6 Enum Types

12.7 named constants

12.8 arrays

12.9 Create your own type

12.1 Introduction to numerical values

The base data type is the block that makes up the data

First, avoid the use of mysterious values

Second, if necessary, you can use hard-coded 0 and 1

Iii. prevention of the exception of 0 errors

Iv. making the conversion of types become apparent

V. Avoiding mixed-type comparisons

VI. Note Compiler warnings

12.2 integers

One, check integer division

Second, check the integer overflow

Third, check the intermediate result overflow

12.3 floating Point

One, to avoid the magnitude difference between the number of the addition and subtraction operations

Second, avoid the equal judgment

Iii. Handling Rounding Error problems: Calculation with higher precision values

Iv. checking language and library support for specific data types

12.4 Characters and strings

First, avoid the use of mysterious characters and mysterious strings

Second, avoid off-by-one errors

Third, understand how your language and development environment support Unicode

Iv. determining internationalization and localization strategies as early as possible in the program life

If you know that you only need to support the language of one text, consider using the ISO8895 character set

Vi. If you need to support multiple languages, use Unicode

Vii. adopting some consistent string-type conversion strategy

Strings in the C language

Note the difference between a string pointer and a character array

Nine, the length of the C-style string is declared as Constant+1

Initialize a string with NULL to avoid a string without a terminator

Xi. replacing pointers in C with character arrays

12. Replace strcpy with strncpy () to avoid a string without a terminator

12.5 Boolean variables

First, using Boolean variables to document the program description

Second, using Boolean variables to simplify complex judgments

Third, create your own Boolean type if needed

12.6 Enum Types

I. Using enumeration types to improve readability

Ii. increasing reliability with enumeration types

Third, use enumeration type to simplify the modification

Iv. The enumeration type as an alternative to a Boolean variable

V. Checking illegal values

Vi. define the first and last items of the enumeration for use with circular boundaries

Vii. leave the first element of the enumeration type as an illegal value

Viii. define the rules for the use of the first and last elements in the project code authoring standard, and maintain consistency when used

Nine, alert to the enumeration elements of the explicit assignment of errors caused by

12.7 named constants

One, the use of a named constant in the data declaration

Second, avoid the use of text, even if it is safe

Iii. using variables or classes with appropriate scopes to simulate named constants

Iv. uniform use of named constants

12.8 arrays

First, verify that all array subscripts do not exceed the bounds of the array

Consider replacing an array with a container (set, stack, queue), or using an array as a sequential structure

Third, check the boundary point of the array

Iv. if the array is multidimensional, confirm that the subscript is in the correct order of use

Five, beware of the next standard series of words

Six combine array_length () macros in C to use arrays

12.9 Create your own type

Principle: 1, to the creation of the type of function-oriented name

2. Avoid using predefined types

3. Do not redefine a pre-defined type

4. Define alternative types for portability

12th Chapter Fundamental Data Types Basic datatype