RAZDEL_4

PROGRAM RAZDEL_4
INTEGER DIFFERENCE
CHARACTER(LEN=10) DATE1, DATE2
READ *, DATE1, DATE2
CALL DIFFERENCE_DATES(DATE1, DATE2, DIFFERENCE)
PRINT *, DIFFERENCE
END PROGRAM

SUBROUTINE DIFFERENCE_DATES(DATE1, DATE2, DIFFERENCE)
CHARACTER(LEN=10) DATE1, DATE2
INTEGER MONTHS(12), DAY1, DAY2, MONTH1, MONTH2, YEAR1, YEAR2, A, B, DIFFERENCE
DO I = 1, 12
IF (I/2*2 /= I) THEN
IF (I == 9 .OR. I == 11) THEN
MONTHS(I) = 30
ELSE
MONTHS(I) = 31
END IF
ELSE
IF (I == 8 .OR. I == 10 .OR. I == 12) THEN
MONTHS(I) = 31
ELSE IF (I == 2) THEN
MONTHS(I) = 28
ELSE
MONTHS(I) = 30
END IF
END IF
END DO
READ(DATE1(1:2), *) DAY1
READ(DATE2(1:2), *) DAY2
READ(DATE1(4:5), *) MONTH1
READ(DATE2(4:5), *) MONTH2
READ(DATE1(7:10), *) YEAR1
READ(DATE2(7:10), *) YEAR2
DIFFERENCE = 0
IF (YEAR1 == YEAR2 .AND. MONTH1 == MONTH2 .AND. DAY1 == DAY2) THEN
RETURN
END IF
IF (ABS(YEAR1 - YEAR2) > 0) THEN
DIFFERENCE = DIFFERENCE + ABS(YEAR1 - YEAR2) * 365
IF (YEAR1 > YEAR2) THEN
B = YEAR1
A = YEAR2
ELSE
A = YEAR1
B = YEAR2
END IF
DO I = A, B
IF (I/4*4 == I) DIFFERENCE = DIFFERENCE + 1
END DO
END IF
IF (MONTH1 > MONTH2) THEN
B = MONTH1
A = MONTH2
DIFFERENCE = DIFFERENCE + DAY1 - DAY2
ELSE
A = MONTH1
B = MONTH2
DIFFERENCE = DIFFERENCE - DAY1 + DAY2
END IF
IF (ABS(MONTH1 - MONTH2) > 0) THEN
IF (YEAR1 == YEAR2 .AND. YEAR1 / 4 * 4 == YEAR1) MONTHS(2) = 29
DO I = A, B-1
DIFFERENCE = DIFFERENCE + MONTHS(I)
END DO
END IF
RETURN
END