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      program simple
      implicit real*8(a-h,o-z)
      double precision a(3,4),b(3,4),c(3,4)
      data a /12.00,11.00,10.00,
     1         9.00, 8.00, 7.00,
     2         6.00, 5.00, 4.00,
     3         3.00, 2.00, 1.00/
      data b /1.00,2.00,3.00,
     1        4.00,5.00,6.00,
     2        7.00,8.00,9.00,
     3       10.00,11.00,12.00/
      open(unit=6,file="Example01-04.out")
      n1 = 3
      n2 = 4
      call addmat(a,b,c,n1,n2)
      do 50 i=1,3
        write(6,100) (a(i,j),j=1,4)
   50 continue
      do 60 i=1,3
        write(6,100) (b(i,j),j=1,4)
   60 continue
      do 70 i=1,3
        write(6,100) (c(i,j),j=1,4)
   70 continue
  100 format(' ',10f10.4)
      end
      subroutine addmat(a,b,c,n1,n2)
      double precision a(n1,n2),b(n1,n2),c(n1,n2)
      do 20 i=1,n1
        do 10 j=1,n2
          c(i,j) = a(i,j) + b(i,j)
   10   continue
   20 continue
      end