View difference between Paste ID: FJL8kdLL and eZCFZppf

 c     Main menu
       PROGRAM main
       IMPLICIT NONE
 
       INTEGER command
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
       COMMON / flag / is_triangle_created
 
       REAL calculate_area, find_min_angle, min_angle_cos
       REAL a, b, alpha
       REAL PI, beta
       LOGICAL is_triangle_created
       is_triangle_created = .FALSE.
       PI = 3.1415927
 
       PRINT *, '1. Create new triangle.'
       PRINT *, '2. Calculate area.'
       PRINT *, '3. Find minimal angle.'
       PRINT *, '4. Find cosin of minimal angle.'
       PRINT *, '5. Exit.'
 c     Delete this
       PRINT *, '6. (temp) Show triangle params.'
 c     Delete this
     1 PRINT *, '>> '
 
       READ *, command
       IF(.NOT. is_triangle_created .AND.
      + (command .EQ. 2 .OR. command .EQ. 3 .OR. command .EQ. 4)) THEN
          PRINT *, 'Error: triangle is not created.'
          GOTO 1
       ENDIF
 
       SELECT CASE (command)
       CASE (1)
          CALL input_triangle
       CASE (2)
          PRINT *, 'Area = ', calculate_area()
       CASE (3)
          PRINT *, 'Minimal angle = ', find_min_angle()
       CASE (4)
          PRINT *, 'Minimal angle cosin = ', min_angle_cos()
       CASE (5)
          GOTO 2
       CASE (6)
 c     Delete this
          CALL write_triangle
 c     Delete this
       CASE default
          PRINT *, 'Unexpected command'
       END SELECT
       GOTO 1
     2 END
 
 c     Triangle creation
       SUBROUTINE input_triangle
       IMPLICIT NONE
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
       COMMON / flag / is_triangle_created
 
       REAL a, b, alpha
       REAL PI, beta
       LOGICAL is_triangle_created
 
     3 PRINT *, 'Enter [a] [b] [alpha]:'
       READ *, a, b, alpha
 
       IF(a .LE. 0 .OR. b .LE. 0 .OR. alpha .LE. 0 .OR.
-     + (a**2 .LE. (b*SIN(alpha))**2)) THEN
+     + (a .LE. b*SIN(alpha * PI/180))) THEN
          PRINT *, 'Error: triangle is not exist'
          GOTO 3
       ENDIF
 
       is_triangle_created = .TRUE.
       PRINT *, 'Triangle is created'
       END
 
 c     Area calculation
       REAL FUNCTION calculate_area()
       IMPLICIT NONE
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
 
       REAL a, b, alpha
       REAL PI, beta
 
       beta = ASIN(b/a * SIN(alpha * PI/180)) * 180/PI
       calculate_area = 0.5 * a * b * SIN((180 - beta - alpha) * PI/180)
 
       RETURN
       END
 
 c     Minimal angle finding
       REAL FUNCTION find_min_angle()
       IMPLICIT NONE
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
 
       REAL a, b, alpha
-      REAL PI, beta, gamma
+
       REAL gamma, minv
 
       beta = ASIN(b/a * SIN(alpha * PI/180)) * 180/PI
       gamma = 180 - alpha - beta
-      IF (alpha .LE. beta .AND. alpha .LE. gamma) THEN
+
-         find_min_angle = alpha
+      minv = alpha
-      ELSEIF (beta .LE. alpha .AND. beta .LE. gamma) THEN
+      IF (beta .LT. minv) THEN
-         find_min_angle = beta
+         minv = beta
-      ELSE
+
-         find_min_angle = gamma
+      IF (gamma .LT. minv) THEN
          minv = gamma
       ENDIF
       find_min_angle = minv
 
       RETURN
       END
 
 c     Calculate cosin of minimal angle
       REAL FUNCTION min_angle_cos()
       IMPLICIT NONE
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
 
       REAL a, b, alpha
       REAL PI, beta, find_min_angle
 
       min_angle_cos = COS(find_min_angle() * PI/180)
       END
 
 c     Delete
       SUBROUTINE write_triangle
 
       COMMON / input / a, b, alpha
       COMMON / utility / PI, beta
 
       REAL a, b, alpha
       REAL PI, beta
 
       PRINT *, 'a = ', a
       PRINT *, 'b = ', b
       PRINT *, 'alpha = ', alpha
 
       END
 c     Delete