[文件读写] Fortran文件读入问题

program main
implicit none
integer::i_node,i_element
integer::n_node1,n_elemnet1,
integer,allocatable::ij_element1(:,:)
real(8),allocatable::coordinate_n1(:,:)

open(unit=4,file='data.txt',form='formatted',status='old')
read(4,*)n_node1,n_element1
allocate(ij_element1(n_node1,4),coordinate_n1&(n_node1,2)

!读入数据.

do i_node=1,n_node1
read(4,*)coordinate_n1(i_node,1),coordinate_n1(i_node,2)
end do
do i_element=1,n_element1
read(4,*)ij_element1(i_element,:)

program main 
    implicit none
    integer::i,x
    real::y,z
    open(12,file="data.txt")
    open(13,file="data1.txt")
    do i=1,100
    read(12,*)x,y,z
    write(*,*)x,y,z
    write(13,*)x,y,z
    enddo
    pause
    end

program Mesh_reflection
implicit none
integer::i_node,i_element
integer::n_node1,n_element1,n_node2,n_element2
integer,allocatable::ij_element1(:,:),ij_element2(:,:)
real(8),allocatable::coordinate_n1(:,:),coordinate_n2(:,:),stress_1(:,:),stress_2(:,:)
open(unit=4,file="data.txt")
open(unit=5,file="mdata_new.txt")
read(4,*)n_node1,n_element1
read(5,*)n_node2,n_element2
allocate(ij_element1(n_node1,4),ij_element2(n_node2,4),coordinate_n1(n_node1,2),coordinate_n2(n_node2,2) ,stress_1(n_node1,4),stress_2(n_node2,4))
!读入数据.
do i_node=1,n_node1
read(4,*)coordinate_n1(i_node,1),coordinate_n1(i_node,2)
end do
do i_element=1,n_element1
read(4,*)ij_element1(i_element,:)
end do
do i_node=1,n_node2
read(5,*)coordinate_n2(i_node,:)
end do
do i_element=1,n_element2
read(5,*)ij_element2(i_element,:)
enddo
write(4,*)coordinate_n1(i_node,1),coordinate_n1(i_node,2)
endprogram

program Mesh_reflection
  implicit none
  integer::i_node,i_element
  integer::n_node1,n_element1!,n_node2 ,n_element2 !//你不需要以 2 结束的变量
  integer,allocatable::ij_element1(:,:)!,ij_element2(:,:)!//同上
  real(8),allocatable::coordinate_n1(:,:)!,coordinate_n2(:,:),stress_1(:,:),stress_2(:,:) !//同上
  open(unit=4,file="data.txt") 
  open(unit=5,file="mdata_new.txt")
  !read(4,*)n_node1,n_element1 // 您的数据文件里并没有 n_node1 ， n_element1
  !read(5,*)n_node2,n_element2 // 同上
  n_node1 = 7751 ; n_element1 = 7647 !// 需要赋值
  allocate(ij_element1(n_node1,4),coordinate_n1(n_node1,2))!// 删掉了不需要的变量
  !读入数据.
  do i_node=1,n_node1
    read(4,*)coordinate_n1(i_node,1),coordinate_n1(i_node,2)
  end do
  do i_element=1,n_element1
    read(4,*)ij_element1(i_element,:)
  end do
  do i_node=1,n_node1 !// n_node2-> n_node1
    write(5,*)coordinate_n1(i_node,:) !// read 改为 write , coordinate_n2 改为 coordinate_n1
  end do
  do i_element=1,n_element1 !// n_element2 -> n_element1
    write(5,*)ij_element1(i_element,:) !// read 改为 write , ij_element2 改为 ij_element1
  enddo
  write(*,*)coordinate_n1(i_node,1),coordinate_n1(i_node,2) !// 4 改为 *
endprogram

Integer Function GetFreeFileUnit()
  Logical :: bOpen
  Integer :: i
  Do i=11,2**20
    Inquire( i , Opened = bOpen )
    IF ( .Not.bOpen ) Exit
  End Do
  FreeFileUnit = i
End Function GetFreeFileUnit