! ------------------------------------------------------ ! Compute the area of a triangle using Heron's formula ! ------------------------------------------------------ PROGRAM HeronFormula IMPLICIT NONE REAL :: a, b, c ! three sides REAL :: s ! half of perimeter REAL :: Area ! triangle area LOGICAL :: Cond_1, Cond_2 ! two logical conditions READ(*,*) a, b, c WRITE(*,*) "a = ", a WRITE(*,*) "b = ", b WRITE(*,*) "c = ", c WRITE(*,*) Cond_1 = (a > 0.) .AND. (b > 0.) .AND. (c > 0.0) Cond_2 = (a+b > c) .AND. (a+c > b) .AND. (b+c > a) IF (Cond_1 .AND. Cond_2) THEN s = (a + b + c) / 2.0 Area = SQRT(s*(s-a)*(s-b)*(s-c)) WRITE(*,*) "Triangle area = ", Area ELSE WRITE(*,*) "ERROR: this is not a triangle!" END IF END PROGRAM HeronFormula