Use of this method results in the first part of the table being sorted by first. By the bubble sort-interchange method the first step is that the second record is compared with the first, and if necessary they are interchanged.

Then the third record is compared with second. If these two records are interchanged the (new) second record is compared with the first, interchanging if necessary.

Next the fourth and third records are compared for possible interchange. Again if an interchange occurs, we go " upward" and compare the third with second record and then possibly to find its proper place, and hence the name "bubble sort" which is applied to this algorithm.

As an example of using the bubble sort interchange algorithm, consider the following set of six records with sort key as indicated.

15
18
20
21
19
25

Comparison of the second and first records results in no change. Similarly comparison of the third and second and of fourth and third records results in no interchange. However, when the fifth and fourth records are compared (19 and 21) an interchange results. Following this comparison of fourth and third (19 and 20 ) results in an interchange, but then the comparison of the third and second records are compared (25 and 21. Since his is last pair of records and no interchange is required, thus sort routine is completed.

TOP

CODE:

IDENTIFICATION DIVISION.
PROGRAM-ID.
ENVIRONMENT DIVISION.
INPUT-OUTPUT SECTION.
FILE-CONTROL.
DATA DIVISION.
WORKING-STORAGE SECTION.
77 N PIC 999.
77 I PIC 999.
77 J PIC 999.
77 K PIC 999.
77 TEMP PIC 999.
77 D PIC X.
01 AAA.
02 A PIC 999 OCCURS 100 TIMES.
PROCEDURE DIVISION.
MAIN.
DISPLAY (1 1) ERASE.
DISPLAY (10, 5) "ENTER HOW MANY NUMBER YOU WANT TO ENTER".
ACCEPT (10, 50) N WITH PROMPT.
DISPLAY (1 1) ERASE.
DISPLAY (6, 30) "INPUT THE NUMBERS".
MOVE 6 TO LIN.
PERFORM ACC-PARA VARYING I FROM 1 BY 1 UNTIL I > N.
PERFORM BUB-PARA VARYING I FROM 1 BY 1 UNTIL I > N.
DISPLAY (1 1) ERASE.
DISPLAY (5, 30) "OUTPUT (BUBBLE SORT)".
DISPLAY (6, 30) "~~~~~~ ~~~~~~ ~~~~".
MOVE 6 TO LIN.
PERFORM DIS-PARA VARYING I FROM 1 BY 1 UNTIL I > N.
STOP RUN.

ACC-PARA.
COMPUTE LIN = LIN + 1.
ACCEPT (LIN, 35) A(I) WITH PROMPT.
IF LIN = 20
DISPLAY (1 1) ERASE
DISPLAY (6, 30) "CONTINUE"
MOVE 6 TO LIN.

BUB-PARA.
COMPUTE K = I + 1.
PERFORM BUB1-PARA VARYING J FROM K BY 1 UNTIL J > N.

BUB1-PARA.
IF A(I) > A(J)
MOVE A(I) TO TEMP
MOVE A(J) TO A(I)
MOVE TEMP TO A(J).

DIS-PARA.
COMPUTE LIN = LIN + 1.
DISPLAY (LIN, 33) A(I).
IF LIN = 20
DISPLAY (24, 30) "PRESS ANY KEY"
ACCEPT D
DISPLAY (1 1) ERASE
MOVE 6 TO LIN.

Output

MAIN MENU

ENTER HOW MANY NUMBER YOU WANT TO ENTER…….6

SUBMENU