Example 3.7

FORTRAN Version

!
      PROGRAM P38
!
!  This program will find the perimeter and the area of a triangle
!
!
     IMPLICIT NONE
     REAL :: A,B,C,PERI,SEMI,AREA
     INTEGER :: N
!
!    Tell program where data for  READ *  is coming from
     OPEN(UNIT=5, FILE='P38.DAT')      ! UNIT=5 is the default input
!
! 
!    READ DATA
!
     DO N=1,20
        READ *,A,B,C
        IF( A == -90.0 ) STOP

        IF( A <= 0 .OR. B <= 0 .OR. C <= 0 ) THEN
          PRINT 5,A,B,C
          PRINT *,'ALL THE VALUES MUST BE POSITIVE.'
5         FORMAT(' A=',F8.3,'  B=',F8.3,' C=',F8.3)
        ELSE
          PERI = A+B+C
          SEMI = PERI/2
          AREA = SEMI * (SEMI-A) * (SEMI-B) * (SEMI-C)
          IF (AREA .LT. 0) THEN
             PRINT 5,A,B,C
             PRINT *,'TWO SIDES SHORTER THAN THIRD'
          ELSE
             PRINT 8,A,B,C,PERI,SQRT(AREA)
8            FORMAT(' A=',F8.3,' B=',F8.3,' C=',F8.3,' PERIMETER =', &
             F8.3,' AREA=',F8.3)
          END IF
        END IF
     END DO
     STOP
     END PROGRAM P38

5  7  3
5 -2 5 
34 62 54
30 5 43
-90 -90 -90

              +--------------------------------------------------+
              |     32-bit Power for Lahey Computer Systems      |
              |   Phar Lap's 386|DOS-Extender(tm) Version 7.0    |
              |  Copyright (C) 1986-94 Phar Lap Software, Inc.   |
              |           Available Memory = 14880 Kb            |
              +--------------------------------------------------+


A=   5.000 B=   7.000 C=   3.000 PERIMETER =  15.000 AREA=   6.495
A=   5.000  B=  -2.000 C=   5.000
ALL THE VALUES MUST BE POSITIVE.
A=  34.000 B=  62.000 C=  54.000 PERIMETER = 150.000 AREA= 916.229
A=  30.000  B=   5.000 C=  43.000
TWO SIDES SHORTER THAN THIRD

Last modified: 08/07/97