fib.cbl

000010 IDENTIFICATION DIVISION.
000020 PROGRAM-ID. fibmain.
000030 ENVIRONMENT DIVISION.
000040 DATA DIVISION.
000050 WORKING-STORAGE SECTION.
000060     77 n USAGE IS BINARY-LONG.
000070 PROCEDURE DIVISION.
000080     MOVE 47 TO n
000090     CALL "fib" USING BY VALUE n RETURNING n.
000100     DISPLAY n
000110     STOP RUN.
000120 END PROGRAM fibmain.
000130
000140 IDENTIFICATION DIVISION.
000150 PROGRAM-ID. fib IS RECURSIVE.
000160 ENVIRONMENT DIVISION.
000170 DATA DIVISION.
000180 LOCAL-STORAGE SECTION.
000190     77 fib1 USAGE IS BINARY-LONG.
000200     77 fib2 USAGE IS BINARY-LONG.
000210 LINKAGE SECTION.
000220     77 n USAGE IS BINARY-LONG.
000230 PROCEDURE DIVISION USING BY VALUE n.
000240     IF n LESS THAN OR EQUAL TO 1
000250         MOVE n TO RETURN-CODE
000260         GOBACK
000270     END-IF
000280
000290     SUBTRACT 1 FROM n
000300     CALL "fib" USING BY VALUE n RETURNING fib1
000310     SUBTRACT 1 FROM n
000320     CALL "fib" USING BY VALUE n RETURNING fib2
000330     COMPUTE RETURN-CODE = fib1 + fib2
000340     GOBACK.
000350 END PROGRAM fib.