Do

写法

Do 变量名=起始是多少, 终点是多少, 每次增加多少
（重复执行的部分）
End Do

如果增量是负，则加到小于终点为止，反之加到大于终点为止
默认增量为1

用例

重复输出

program hello

    implicit none
    integer::x

    do x=1,10
    print *, "Hello World!"
    end do

    print *, ""
    print *, "press any key to continue"
    read *,

end program

 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!
 Hello World!

 press any key to continue

常用对数log₁₀计算

program log

implicit none
integer::x
real::y, z

print *, '  数               常用对数'
do x=0,6
y=10**x
z=log10(y)
print *, y, z
end do

print *, ""
print *, "press any key to continue"
read *,

end

       数               常用对数
       1.00000000       0.00000000
       10.0000000       1.00000000
       100.000000       2.00000000
       1000.00000       3.00000000
       10000.0000       4.00000000
       100000.000       5.00000000
       1000000.00       6.00000000
    
     press any key to continue

三角函数表

program tri
implicit none
    integer::degree
    real::radian,s,c,t,x

    print *, 'degree  sin    cos      tan'
    radian=3.1415926/180

    do degree=0,180,30
      x=real(degree)*radian
      s=sin(x)
      c=cos(x)
      t=tan(x)
      print "(i3,3f9.4)",degree,s,c,t
    end do

    print *, ""
    print *, "press any key to continue"
    read *,
    
end

 degree  sin    cos      tan
  0   0.0000   1.0000   0.0000
 30   0.5000   0.8660   0.5774
 60   0.8660   0.5000   1.7321
 90   1.0000  -0.0000*********
120   0.8660  -0.5000  -1.7321
150   0.5000  -0.8660  -0.5774
180  -0.0000  -1.0000   0.0000

 press any key to continue

麦克劳林级数

自然对数

program e

implicit none
integer::n,b
real::c,s

print *,"输入n"
read *, n

c=1.0
s=1.0
do b=1,n
c=c/real(b)
s=s+c
end do

print *, "e=", s

print *, ""
print *, "press any key to continue"
read *,

end

 输入n
666
 e=   2.71828198

 press any key to continue

正弦

program msin
    implicit none
    integer::n,b,degree
    real::c,s,x,y,radian

    print *, 'n,degree='
    read *, n,degree

    radian=3.14159265358979323846/180.0
    x=real(degree)*radian
    y=sin(x)

    c=x
    s=x
    do b=1,n
        c=c*(-1)*(x**2)/(2*real(b))/(2*real(b)+1)
        s=s+c
    end do

    print *, 'sin x=',s
    print *, 'sin x(comparison)=',y

    print *, ''
    print *, 'press any key to continue'
    read *,

end

 n,degree=
 10000,225
 sin x= -0.707106829
 sin x(comparison)= -0.707106709

 press any key to continue

傅里叶级数

其中b_n=(-1)^n-1/n，对于输入的n，列出x=0，0.1，0.2，···，2.0时的计算值

program fourier
  implicit none
  integer::n,i,x
  real::s,a

  print *, 'enter a value for n'
  read *, n
  print *, '   10 times x','   sum'
  do x=0,20
    s=0
    do i=1,n
      a=(-1)**(real(i)-1)*(sin(real(i)*0.1*real(x)))/(real(i))
      s=s+a
    end do
    print *, x,s
  end do
  print *, ''
  print *, 'press any key to continue'
  read *,
end

 enter a value for n
66666
  10 times x   sum
           0   0.00000000
           1   4.99984734E-02
           2   9.99970958E-02
           3  0.149997145
           4  0.199994281
           5  0.249995768
           6  0.299991280
           7  0.349991828
           8  0.399990231
           9  0.449990660
          10  0.499992847
          11  0.549987793
          12  0.599990606
          13  0.649989665
          14  0.699990153
          15  0.750003338
          16  0.799997866
          17  0.850003183
          18  0.900006533
          19  0.949996352
          20  0.999998331

 press any key to continue