program average
        real x, y, z
        print *, "Enter the two numbers you want to average:"
        read *, x, y
        call avg(x,y,z)
        print *, "The average is", z
        print *, "Bye"
        end

        subroutine avg(a,b,c)
        real a, b, c
        c = (a + b)/2.
        end