Primes by Trial Division - FORTRAN IV

26 July 2020
No block-form conditionals—single statements only. Output format statement mandatory for TTY.
INTEGER UNIT, FOUND, COUNT, I, PRIMES(100)
UNIT = 4
FOUND = 0
COUNT = 2
10 FOUND = FOUND + 1
WRITE (UNIT,900) COUNT
900 FORMAT (I6)
PRIMES(FOUND) = COUNT
COUNT = COUNT + 1
I = 1
19 IF (FOUND .LT. 100) GOTO 20
GOTO 30
20 IF (MOD(COUNT,PRIMES(I)) .EQ. 0) GOTO 21
GOTO 22
21 COUNT = COUNT + 1
I = 1
GOTO 20
22 IF (I .EQ. FOUND) GOTO 10
I = I + 1
GOTO 19
30 STOP
END