COBOL-内部排序

COBOL是一种大型商业应用程序的语言，很多企业使用COBOL来处理其核心业务。内部排序是COBOL中一个非常重要的功能，可以对数组或表格中的数据进行排序，提高程序运行效率和数据处理能力。

排序算法

COBOL内部排序支持多种排序算法，包括冒泡排序、选择排序、插入排序、快速排序等。下面是一个简单的COBOL程序示例，演示如何使用快速排序算法对一个数组进行排序：

IDENTIFICATION DIVISION.
PROGRAM-ID. SORT-EXAMPLE.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 ARRAY OCCURS 10 TIMES.
   05 ELEMENT PIC 9(4).
01 I PIC 9(2).
01 J PIC 9(2).

PROCEDURE DIVISION.
   MOVE 34 TO ARRAY(1)
   MOVE 12 TO ARRAY(2)
   MOVE 83 TO ARRAY(3)
   MOVE 45 TO ARRAY(4)
   MOVE 55 TO ARRAY(5)
   MOVE 29 TO ARRAY(6)
   MOVE 67 TO ARRAY(7)
   MOVE 17 TO ARRAY(8)
   MOVE 39 TO ARRAY(9)
   MOVE 72 TO ARRAY(10)
   CALL "QSORT" USING ARRAY, 1, 10
   DISPLAY "Sorted array:"
   PERFORM UNTIL I > 10
      DISPLAY ARRAY(I)
      ADD 1 TO I
   END-PERFORM
   STOP RUN.

QSORT SECTION.
   ACCEPT QS-ARRAY USING A-ARRAY, A-LEFT, A-RIGHT.
   IF A-LEFT < A-RIGHT
      PERFORM VARYING I FROM A-LEFT BY 1
         UNTIL A-ARRAY(I) >= A-ARRAY((A-LEFT+A-RIGHT)/2)
      PERFORM VARYING J FROM A-RIGHT BY -1
         UNTIL A-ARRAY(J) <= A-ARRAY((A-LEFT+A-RIGHT)/2)
      IF I <= J
         PERFORM SWAP USING A-ARRAY, I, J
         ADD 1 TO I
         ADD -1 TO J
      END-IF
      IF A-LEFT < J PERFORM QSORT USING A-ARRAY, A-LEFT, J
      IF I < A-RIGHT PERFORM QSORT USING A-ARRAY, I, A-RIGHT
   END-IF.

SWAP SECTION.
   ACCEPT SW-ARRAY USING S-ARRAY, S-I, S-J.
   MOVE S-ARRAY(S-I) TO TEMP
   MOVE S-ARRAY(S-J) TO S-ARRAY(S-I)
   MOVE TEMP TO S-ARRAY(S-J).

排序函数

除了排序算法外，COBOL还提供了内置的排序函数，可以方便地对表格数据进行排序。下面是一个简单的COBOL程序示例，演示如何使用SORT函数对一个表格进行排序：

IDENTIFICATION DIVISION.
PROGRAM-ID. SORT-EXAMPLE.

DATA DIVISION.
WORKING-STORAGE SECTION.
01 TABLE OCCURS 10 TIMES.
   05 NAME PIC X(10).
   05 AGE PIC 9(3).
01 WS-SORT WORKING-STORAGE PIC X(10).

PROCEDURE DIVISION.
   MOVE "DAVID" TO TABLE(1).NAME
   MOVE 23 TO TABLE(1).AGE
   MOVE "ALICE" TO TABLE(2).NAME
   MOVE 42 TO TABLE(2).AGE
   MOVE "BOB" TO TABLE(3).NAME
   MOVE 37 TO TABLE(3).AGE
   MOVE "CHARLES" TO TABLE(4).NAME
   MOVE 18 TO TABLE(4).AGE
   MOVE "EMILY" TO TABLE(5).NAME
   MOVE 31 TO TABLE(5).AGE
   MOVE "FRANK" TO TABLE(6).NAME
   MOVE 54 TO TABLE(6).AGE
   MOVE "GEORGE" TO TABLE(7).NAME
   MOVE 26 TO TABLE(7).AGE
   MOVE "HENRY" TO TABLE(8).NAME
   MOVE 29 TO TABLE(8).AGE
   MOVE "IVAN" TO TABLE(9).NAME
   MOVE 40 TO TABLE(9).AGE
   MOVE "JANE" TO TABLE(10).NAME
   MOVE 20 TO TABLE(10).AGE
   MOVE "NAME" TO WS-SORT
   SORT TABLE ASCENDING KEY NAME USING WS-SORT
   DISPLAY "Sorted table:"
   PERFORM VARYING I FROM 1 BY 1 UNTIL
   I > 10
      DISPLAY TABLE(I).NAME TABLE(I).AGE
   END-PERFORM.
   MOVE "AGE" TO WS-SORT
   SORT TABLE ASCENDING KEY AGE USING WS-SORT
   DISPLAY "Sorted table:"
   PERFORM VARYING I FROM 1 BY 1 UNTIL
   I > 10
      DISPLAY TABLE(I).NAME TABLE(I).AGE
   END-PERFORM.
   STOP RUN.

结论

COBOL内部排序是非常重要的程序员工具，可以大大提高程序运行效率和数据处理能力。开发人员可以选择适合自己需要的排序算法或排序函数，完成数据的排序。