fortran中函数形式输出数组元素的第二大值

 

001、

root@ubuntu26:/home/test01/fortran02# cat test01.f90      ## 测试程序
program test01_fortran
    implicit none
    integer,allocatable :: ay1(:)
    integer :: a,i,result
    do
        write(*, "(A)", advance="no") "input a: "; read *, a
        if(a >= 2) then
            exit
        end if
        print *, "a must be >= 2"
    end do
    allocate(ay1(a))
    do i = 1, a
        write(*, "(A, I0, A)", advance="no") "input ay1(", i, "): "
        read *, ay1(i)
    end do
    result = second_max(ay1)
    print *, "result = ", result
    deallocate(ay1)
contains
    integer function second_max(x)
        implicit none
        integer,intent(in) :: x(:)
        integer :: max1, max2,i
        if(all(x == x(1))) then
            error stop "all the elements are same!"
        end if
        max1 = maxval(x); max2=minval(x)
        do i = 1,size(x)
            if(x(i) < max1 .AND. x(i) > max2) then
                max2 = x(i)
            end if
        end do
        second_max = max2
    end function second_max
end program test01_fortran
root@ubuntu26:/home/test01/fortran02# gfortran test01.f90 -Wall -O2 -o kkk
root@ubuntu26:/home/test01/fortran02# ls
kkk  test01.f90
root@ubuntu26:/home/test01/fortran02# ./kkk                ## 测试
input a: 4
input ay1(1): 33
input ay1(2): 44
input ay1(3): 99
input ay1(4): 33
 result =           44
root@ubuntu26:/home/test01/fortran02# ./kkk
input a: 0
 a must be >= 2
input a: 3
input ay1(1): 33
input ay1(2): 88
input ay1(3): 22
 result =           33

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