Update fortran_ex.md

WonyoungCho · Nov 24, 2018 · 7d95502 · 7d95502
1 parent ef2b0b7
commit 7d95502
Showing 1 changed file with 50 additions and 9 deletions.
diff --git a/docs/fortran_ex.md b/docs/fortran_ex.md
@@ -148,7 +148,9 @@ $ ./a.out
 
 # Array
 
-- **Example - static**
+- **Example - static array**
+
+고정된 크기를 가지는 행렬이다.
 ```fortran
 real a, b, c
 dimension a(100), b(10,10), c(2,3,4)
@@ -168,7 +170,9 @@ or
 real a(1:100), b(3:12,2:11), c(1:2,4:6,3:6)
 ```
 
-- **Example - dynamic**
+- **Example - dynamic array**
+
+차원만 정해놓고 크기는 정해놓지 않은 행렬을 말한다.
 ```fortran
 integer, dimension(:), allocatable :: string   ! 1D
 ```
@@ -194,12 +198,49 @@ $ ./a.out
           10          10          10          10          10
 ```
 
-- **Example - pointer**
-```fortran
-real, target :: b(100,100)
-real, pointer :: u(:,:), v(:), w(:,:)
+- **Example - pointer array**
 
-u => b(i:i+2, j:j+2)
-allocate(w(m,n))
-v => b(:,j)
+행렬의 값을 **point**해서 가져간다.
+```fortran
+program pointer
+  implicit none
+  integer :: l, i, j, k, m, n
+  real, target :: b(6,6)=1
+  real, pointer :: u(:,:), v(:), w(:,:)
+  print *, b
+  print *, '---------'  
+  m=3; n=2
+  i=2; j=4
+  n=6
+  do k=1,6
+     do l=1,6
+        b(l,k)=2*l+k
+     end do
+  end do
+  print *, b
+  print *, '---------'  
+  u => b(i:i+2, j:j+2)
+  print *, u
+  print *, '---------'  
+  allocate(w(m,n))
+  w = 9
+  v => b(:,j)
+  print *, v  
+  print *, '---------'  
+  v => w(i-1, 1:n:2)
+
+  print *, v
+end program pointer
+```
+```sh
+$ ./a.out
+   1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000       1.00000000    
+ ---------
+   3.00000000       5.00000000       7.00000000       9.00000000       11.0000000       13.0000000       4.00000000       6.00000000       8.00000000       10.0000000       12.0000000       14.0000000       5.00000000       7.00000000       9.00000000       11.0000000       13.0000000       15.0000000       6.00000000       8.00000000       10.0000000       12.0000000       14.0000000       16.0000000       7.00000000       9.00000000       11.0000000       13.0000000       15.0000000       17.0000000       8.00000000       10.0000000       12.0000000       14.0000000       16.0000000       18.0000000    
+ ---------
+   8.00000000       10.0000000       12.0000000       9.00000000       11.0000000       13.0000000       10.0000000       12.0000000       14.0000000    
+ ---------
+   6.00000000       8.00000000       10.0000000       12.0000000       14.0000000       16.0000000    
+ ---------
+   9.00000000       9.00000000       9.00000000
 ```