identification division.

program-id. sort-merge-test.

environment division.

input-output section.

file-control.

select sortfile1 assign to "sortfile1.dat"

organization is line sequential.

select sortfile2 assign to "sortfile2.dat"

organization is line sequential.

select sortfile3 assign to "sortfile3.dat"

organization is line sequential.

select sortwork assign to "sortwork.dat".

select sorted1 assign to "sorted1.dat"

organization is line sequential.

select sorted2 assign to "sorted2.dat"

organization is line sequential.

select sorted3 assign to "sorted3.dat"

organization is line sequential.

select merged assign to "merged.dat"

organization is line sequential.

data division.

file section.

fd sortfile1.

01 sortrec1 pic x(48).

fd sortfile2.

01 sortrec2 pic x(48).

fd sortfile3.

01 sortrec3 pic x(48).

sd sortwork.

01 sortrecwork.

05 fran-num-in pic 99.

05 empl-num-in pic 9999.

05 filler pic x(42).

fd sorted1.

01 sortedrec1 pic x(48).

fd sorted2.

01 sortedrec2 pic x(48).

fd sorted3.

01 sortedrec3 pic x(48).

fd merged.

01 mergedrec pic x(48).

procedure division.

100-main.

sort sortwork

on ascending key fran-num-in

empl-num-in

using sortfile1

giving sorted1.

sort sortwork

on ascending key fran-num-in

empl-num-in

using sortfile2

giving sorted2.

sort sortwork

on ascending key fran-num-in

empl-num-in

using sortfile3

giving sorted3.

merge sortwork

on ascending key fran-num-in empl-num-in

using sorted1 sorted2 sorted3

giving merged.

********************************************************

merge sortwork

on ascending key fran-num-in

empl-num-in

using sortfile1 sortfile2 sortfile3

giving sorted1.

sort sortwork

on ascending key fran-num-in empl-num-in

using sorted1

giving sorted2.

********************************************************

sort sortwork

on ascending key fran-num-in empl-num-in

using sortfile1 sortfile2 sortfile3

giving sorted1.

stop run.