代码的环复杂度(Cyclomatic complexity，有的地方又翻译成圈复杂度)是一种代码复杂度的衡量标准，在1976年由Thomas J. McCabe, Sr. 提出。

在软件测试的概念里，圈复杂度用来衡量一个模块判定结构的复杂程度，数量上表现为独立线性路径条数，即合理的预防错误所需测试的最少路径条数。圈复杂度大说明程序代码可能质量低且难于测试和维护。

计算公式

环复杂度 = E − N + 2

E = 程序控制流图中边的个数

N = 程序控制流图中点的个数

看个具体的例子。下面这段ABAP代码的环复杂度根据公式计算为3.

DATA: lv_value TYPE i VALUE 1. 
IF lv_value = 1. 
    WRITE: / 'always happend'. 
ELSEIF lv_value = 2. 
    WRITE: / 'not possible'. 
ELSE. 
    WRITE: / 'even not possible'. 
ENDIF.

先把代码的程序流图画出来：

在ABAP里用Code inspector这个工具测量代码的环复杂度：

具体步骤参考我的ABAP博客:

• A Small tip to get all transparent tables used in ABAP code

• Useful tips regarding ABAP code inspector that you may not know

而Java可以用一个叫做SourceMonitor的工具测量环复杂度：

详细使用参考我的博客Use SourceMonitor to monitor your java code complexity

如何查看某个用户指定时间段的ABAP开发记录

输入用户名和想查询的时间段：

执行得到结果。双击可查看具体代码：

工具源代码：

REPORT tool_dev_history.

PARAMETERS: name TYPE usr02-bname OBLIGATORY,

            fro  TYPE sy-datum OBLIGATORY DEFAULT sy-datum,

            to_  TYPE sy-datum OBLIGATORY DEFAULT sy-datum.

CONSTANTS: c_name TYPE trdir-name VALUE 'Name',

           c_date TYPE trdir-udat VALUE 'Date'.

AT SELECTION-SCREEN.

  IF fro > to_.

    WRITE: / 'Invalid date period.' COLOR COL_NEGATIVE.

    RETURN.

  ENDIF.

START-OF-SELECTION.

  DATA: lt_record TYPE STANDARD TABLE OF trdir.

  SELECT name udat INTO CORRESPONDING FIELDS OF TABLE lt_record FROM trdir

     WHERE unam = name AND udat BETWEEN fro AND to_.

  IF sy-subrc <> 0.

    WRITE: / 'No record found at given date period.' COLOR COL_NEGATIVE.

    RETURN.

  ENDIF.

  SORT lt_record BY udat DESCENDING.

  WRITE:  10 c_name, 80 c_date.

  LOOP AT lt_record INTO DATA(ls_data).

    WRITE: / ls_data-name UNDER c_name COLOR COL_POSITIVE, ls_data-udat UNDER c_date COLOR COL_TOTAL.

    HIDE ls_data-name.

  ENDLOOP.

AT LINE-SELECTION.

  DATA: bdcdata_tab  TYPE TABLE OF bdcdata,

        opt          TYPE ctu_params,

        bdcdata_line TYPE bdcdata.

  bdcdata_line-program = 'SAPLWBABAP'.

  bdcdata_line-dynpro = '0100'.

  bdcdata_line-dynbegin = 'X'.

  APPEND bdcdata_line TO bdcdata_tab.

  CLEAR: bdcdata_line.

  bdcdata_line-fnam = 'BDC_CURSOR'.

  bdcdata_line-fval = 'RS38M-PROGRAMM'.

  APPEND bdcdata_line TO bdcdata_tab.

  CLEAR: bdcdata_line.

  bdcdata_line-fnam = 'BDC_OKCODE'.

  bdcdata_line-fval = '=SHOP'.

  APPEND bdcdata_line TO bdcdata_tab.

  CLEAR: bdcdata_line.

  bdcdata_line-fnam = 'RS38M-PROGRAMM'.

  bdcdata_line-fval = ls_data-name.

  APPEND bdcdata_line TO bdcdata_tab.

  opt-dismode = 'E'.

  opt-defsize = 'X'.

  CALL TRANSACTION 'SE38' USING bdcdata_tab  OPTIONS FROM opt.

  CLEAR: bdcdata_tab.