Fortran使用隐形DO循環和reshape給一維和多元數組賦初值

Fortran可以使用隐形DO循環和reshape給一維和多元數組賦初值.

下面以一維數組和二維數組為例,并給出程式結果:

program main
implicit none
integer::i,j
integer::a(3)=(/(3*j,j=1,3,1)/)
integer::b(6)=(/((i,i=1,2),4*j,j=1,2,1)/)
real::c(2,4)=reshape((/1,(i,i=3,8),10/),(/2,4/))

write(*,*) 'a(3):',a
write(*,*) 'b(6):',b

write(*,*)  '!---------------------------------------'
write(*,*) 'c(1,:)',c(1,:)
write(*,*) 'c(2,:)',c(2,:)
write(*,*)  '!-----------------------------------------'

end program main
      

輸出結果如下:

賦初值時可能符号(/,...,/)看着不太舒服,gfortran容許使用'['和']'來代替:

program main
implicit none
integer::i,j
integer::a(3)=[(3*j,j=1,3,1)]
integer::b(6)=[((i,i=1,2),4*j,j=1,2,1)]
real::c(2,4)=reshape([1,(i,i=3,8),10],(/2,4/))

write(*,*) 'a(3):',a
write(*,*) 'b(6):',b

write(*,*)  '!---------------------------------------'
write(*,*) 'c(1,:)',c(1,:)
write(*,*) 'c(2,:)',c(2,:)
write(*,*)  '!-----------------------------------------'

end program main