The Practice of Programming
In the preface, the author illustrates four basic principles of programming - simplicity, clarity, generality, automation.
I suppose that everyone has his own programming experience and preference, but with predecessors' valuable guidence, chances are that we can write more beautiful code.
Pieces of summaries and abstracts are organized as follows:
Charpter 1 STYLE
The purpose of style is to make the code easy to read for yourself and others, and good style is crucial to good programming.
Names
- descriptive names for globals, short names for locals
- names with p for pointers; initial capital letters for Globals; all capitals for CONSTANTS; active names for functions
- be consistent
Expressions and Statements
- avoid negative expressions possibly
- use parentheses in mixed unrelated operators
1 the relational operators (< == !=) have higher precedence than the logical operators (&& || ); 2 the logical operators bind tighter than assignment ( = ); 3 the bitwise operators (& |) have lower precedence than relational operators ( == )
- break up complex expressions
- be careful with side effects: (e.g. the following expression is wrong)
scanf("%d %d", &yr, &profit[yr]);X
Consistency and Idioms
- Use a consistent indentation and brace style
- Use idioms for consistency
Wrong code: gets(buf);X //never use 'gets', 'fgets' is better p = malloc(strlen(buf)); strcpy(p, buf);X //strlen does not count the ' ' that terminates a string, while strcpy copies itRight code: p = malloc(strlen(buf)+1); strcpy(p, buf);- the return value from malloc, realloc, strdup, or any other allocation routine should always be checked
Function Macros
One of the most serious problems with function macros is that a parameter that appears more than once in the definition might be evaluated more than once
Magic Numbers
By giving names to the principal numbers in the calculation, we can make the code easier to follow
Define numbers as constants, not macros
const int MAXROW = 24. MAXCOL = 80;static final int MAXROW = 24, MAXCOL = 80;C also has const values but they cannot be used as array bounds, so the enum statement remains the method of choice in C.Use the language to calculate the size of an object
sizeof (int) sizeof(array[0]) sizeof(buf)
Comments
- Comment functions and global data
Sometimes code is genuinely difficult, perhaps because the algorithm is complicated or the data structures are intricate. In that case, a comment that points to a source of understanding can aid the reader
Don't comment bad code, rewrite it
Don't contradict the code. When you change code, make sure the comments are still accurate