代码大全学习-15-基础数据类型(Fundamental Data Types)

这一章没什么好说的，需要注意的checklist里都列出来了，用的时候一条一条对着看就行了。

Checklist: Fundamental Data Types

Numbers in General

• Does the code avoid magic numbers? 
• Does the code anticipate divide-by-zero errors? 
• Are type conversions obvious? 
• If variables with two different types are used in the same expression, will the expression be evaluated as you intend it to be? 
• Does the code avoid mixed-type comparisons? 
• Does the program compile with no warnings? 

Integers

• Do expressions that use integer division work the way they're meant to? 
• Do integer expressions avoid integer-overflow problems? 

Floating-Point Numbers

• Does the code avoid additions and subtractions on numbers with greatly different magnitudes? 
• Does the code systematically prevent rounding errors? 
• Does the code avoid comparing floating-point numbers for equality? 

Characters and Strings

• Does the code avoid magic characters and strings? 
• Are references to strings free of off-by-one errors? 
• Does C code treat string pointers and character arrays differently? 
• Does C code follow the convention of declaring strings to be length constant+1? 
• Does C code use arrays of characters rather than pointers, when appropriate? 
• Does C code initialize strings to NULLs to avoid endless strings? 
• Does C code use strncpy() rather than strcpy()? And strncat() and strncmp()?

Boolean Variables

• Does the program use additional boolean variables to document conditional tests? 
• Does the program use additional boolean variables to simplify conditional tests? 

Enumerated Types

• Does the program use enumerated types instead of named constants for their improved readability, reliability, and modifiability? 
• Does the program use enumerated types instead of boolean variables when a variable's use cannot be completely captured with TRUE and FALSE? 
• Do tests using enumerated types test for invalid values? 
• Is the first entry in an enumerated type reserved for "invalid"? 

Named Constants

• Does the program use named constants for data declarations and loop limits rather than magic numbers? 
• Have named constants been used consistently-not named constants in some places, literals in others? 

Arrays

• Are all array indexes within the bounds of the array? 
• Are array references free of off-by-one errors? 
• Are all subscripts on multidimensional arrays in the correct order? 
• In nested loops, is the correct variable used as the array subscript, avoiding loop-index cross talk? 

Creating Types

• Does the program use a different type for each kind of data that might change? 
• Are type names oriented toward the real-world entities the types represent rather than toward programming-language types? 
• Are the type names descriptive enough to help document data declarations? 
• Have you avoided redefining predefined types? 
• Have you considered creating a new class rather than simply redefining a type?