良好的编程习惯，你知道多少呢？你又用过多少呢？<一>
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//X8023Z 2009.3.2
Good Programming Practice
1,Read the manuals for the version of C++ you are using.
Refer to these manuals frequently to be sure you are aware of the rich collections of C++ features and that you are using them correctly.
2,Your computer and compiler are good teachers.
If after reading your C++ language manuals ,
you still are not sure how a feature of C++ works,
experiment using a small "test program" and see what happens.
Set your complier options for "maximum warnings".
Study each message that the compiler generates and correct the program to eliminate the messages.
3,Every program should begin with a comment that describes the purpose of the program,author,date and time.
4,Use blank lines and space characters to enhance program readability.
5,Many programmers make the last character printed by a function a newline(\n).
This ensures that the function will leave the screen cursor positioned at the beginning of anew line.
Conventions of this nature encourage software reusability-a key goal in software development.
6,Indent the entire body of each function one level within the braces that delimit the body of the function.
This makes a program's funcitonal structure stand out and helps make the program easier to read.
7,Set a convention for the size of indent you prefer,then apply it uniformly.
The tab key may be used to create indents,but tab stops may vary.
We recommend using either 1/4-inch tab stops or(preferably)three spaces form a level of indent.
8,Place a space after each comma(,)to make programs more readable.
9,Some programmers prefer to declare each variable on a separate line.
This format allows for easy insetion of a descriptive comment next to each declaration.
10,Choosing meaningful identifiers helpsp make a program self-documenting--a person can understand the program identifiers.
Use identifiers of 31 characters or fewer to ensure portablitity.
11,Avoid using abbreviations in identifiers.This promotes program readability.
12,Avoid identifiers that begin with underscores and double underscores,
because C++ compilers may use names like that for their own purposes internally.
This will prevent names you choose from being confused with names the compilers choose.
13,Always place a blank line between a declaration and adjacent executable statements.
This makes the declarations stand out in the program and contributes to program clarity.
14,If you prefer to place declarations at the beginning of a function,
separate them from the executable statements in that function with one blank line
to highlight where the declarations end and the executable statements begin.
15，Place spaces on either side of a binary operator.
This makes the operator stand out and makes the program more readable.
16,Using redundant parentheses in complex arithmetic expressions can make the expressions clearer.
17,Place using declarations immediately after the #inclue to which they refer.
18,Indent the statement(s) in the body of an if statement to enhance readability.
19,For readability,there should be no more than one statement per line ina program.
20,A lengthy statement may bespread over several lines.
If a single statement must be split a cross lines,
choose meaningful breaking points,such as aftera comma ina comma-separated list,
or after an operator in a lengthy expression.
If a statement is split across two or more lines,indent all subsequent lines and left-align the group.
21,Refer to the operator precedence and associativity chart when writing expressions containing many operators.
Confirm that the operators in the expression are performed in the order you expect.
If you are uncertain about the order of evaluation in a complex expression,
break the expression into smaller statements or use parentheses to force the order of evaluation.
exactly as you would do in algebraic expression.
Be sure to observe that some operators such as assignment(=)associate right to left rather than left to right.
//X8023Z 2009.3.2
Good Programming Practice
1,Read the manuals for the version of C++ you are using.
Refer to these manuals frequently to be sure you are aware of the rich collections of C++ features and that you are using them correctly.
2,Your computer and compiler are good teachers.
If after reading your C++ language manuals ,
you still are not sure how a feature of C++ works,
experiment using a small "test program" and see what happens.
Set your complier options for "maximum warnings".
Study each message that the compiler generates and correct the program to eliminate the messages.
3,Every program should begin with a comment that describes the purpose of the program,author,date and time.
4,Use blank lines and space characters to enhance program readability.
5,Many programmers make the last character printed by a function a newline(\n).
This ensures that the function will leave the screen cursor positioned at the beginning of anew line.
Conventions of this nature encourage software reusability-a key goal in software development.
6,Indent the entire body of each function one level within the braces that delimit the body of the function.
This makes a program's funcitonal structure stand out and helps make the program easier to read.
7,Set a convention for the size of indent you prefer,then apply it uniformly.
The tab key may be used to create indents,but tab stops may vary.
We recommend using either 1/4-inch tab stops or(preferably)three spaces form a level of indent.
8,Place a space after each comma(,)to make programs more readable.
9,Some programmers prefer to declare each variable on a separate line.
This format allows for easy insetion of a descriptive comment next to each declaration.
10,Choosing meaningful identifiers helpsp make a program self-documenting--a person can understand the program identifiers.
Use identifiers of 31 characters or fewer to ensure portablitity.
11,Avoid using abbreviations in identifiers.This promotes program readability.
12,Avoid identifiers that begin with underscores and double underscores,
because C++ compilers may use names like that for their own purposes internally.
This will prevent names you choose from being confused with names the compilers choose.
13,Always place a blank line between a declaration and adjacent executable statements.
This makes the declarations stand out in the program and contributes to program clarity.
14,If you prefer to place declarations at the beginning of a function,
separate them from the executable statements in that function with one blank line
to highlight where the declarations end and the executable statements begin.
15，Place spaces on either side of a binary operator.
This makes the operator stand out and makes the program more readable.
16,Using redundant parentheses in complex arithmetic expressions can make the expressions clearer.
17,Place using declarations immediately after the #inclue to which they refer.
18,Indent the statement(s) in the body of an if statement to enhance readability.
19,For readability,there should be no more than one statement per line ina program.
20,A lengthy statement may bespread over several lines.
If a single statement must be split a cross lines,
choose meaningful breaking points,such as aftera comma ina comma-separated list,
or after an operator in a lengthy expression.
If a statement is split across two or more lines,indent all subsequent lines and left-align the group.
21,Refer to the operator precedence and associativity chart when writing expressions containing many operators.
Confirm that the operators in the expression are performed in the order you expect.
If you are uncertain about the order of evaluation in a complex expression,
break the expression into smaller statements or use parentheses to force the order of evaluation.
exactly as you would do in algebraic expression.
Be sure to observe that some operators such as assignment(=)associate right to left rather than left to right.
