计算机fortran课程设计(1)

程序编写如下：

real,allocatable::a(:,:),b(:),c(:) print*,'输入未知数个数n' read*,n

allocate(a(n,n)) allocate(b(n)) allocate(c(n))

print*,'输入系数矩阵a' call input(a,n)

print*,'输入等值矩阵b' read*,b

print*,'联立方程组' call output(a,b,n)

call Gauss_jordan(a,b,c,n) print*,\求解\do i=1,n

print 10,i,c(i) enddo

10 format('x',i1,'=',f8.4) deallocate(a) deallocate(b) deallocate(c)

end

subroutine input(a,n) real a(n,n) do i=1,n

read*,(a(i,j),j=1,n) enddo end

subroutine Gauss_jordan(a,b,c,n) dimension a(n,n),b(n),c(n) call up(a,b,n) call low(a,b,n) forall(i=1:n) c(i)=b(i)/a(i,i) endforall end

subroutine output(a,b,n) real a(n,n),b(n) do i=1,n

print 10,a(1,1),i do j=2,n

if(a(i,j)>0)then print 20,a(i,j),j

else

print 30,abs(a(i,j)),j endif enddo

print 40,b(i) enddo

10 format(f5.2,'x',i1\\) 20 format('+',f5.2,'x',i1\\) 30 format('-',f5.2,'x',i1\\) 40 format('=',f8.4) end

subroutine up(a,b,n) real a(n,n),b(n) do i=1,n-1 do j=i+1,n

p=a(j,i)/a(i,i)

a(j,i:n)=a(j,i:n)-a(i,i:n)*p b(j)=b(j)-b(i)*p enddo enddo end

subroutine low(a,b,n)

real a(n,n),b(n) do i=n,2,-1

do j=i-1,1,-1

p=a(j,i)/a(i,i)

a(j,1:i)=a(j,1:i)-a(i,1:i)*p b(j)=b(j)-b(i)*p enddo enddo end

方程组运行结果