📅 最后修改于: 2020-11-04 06:19:01 🧑 作者: Mango
到目前为止，我们已经看到我们可以使用read *语句从键盘读取数据，并分别使用print *语句在屏幕上显示输出。输入输出的这种形式是自由格式I / O，称为列表定向输入输出。
自由格式的简单I / O的格式为-
read(*,*) item1, item2, item3...
print *, item1, item2, item3
write(*,*) item1, item2, item3...
但是，格式化的I / O使您在数据传输方面更具灵活性。
格式化的输入输出的语法如下-
read fmt, variable_list
print fmt, variable_list
write fmt, variable_list
哪里，
fmt是格式规范
variable-list是要从键盘读取或在屏幕上写入的变量的列表
格式规范定义了格式化数据的显示方式。它由一个字符串组成，在括号中包含一个编辑描述符列表。
编辑描述符指定确切的格式，例如宽度，小数点后的数字等，其中显示字符和数字。
Print "(f6.3)", pi
下表描述了描述符-
| Descriptor | Description | Example |
|---|---|---|
| I |
This is used for integer output. This takes the form ‘rIw.m’ where the meanings of r, w and m are given in the table below. Integer values are right justified in their fields. If the field width is not large enough to accommodate an integer then the field is filled with asterisks. |
print “(3i5)”, i, j, k |
| F |
This is used for real number output. This takes the form ‘rFw.d’ where the meanings of r, w and d are given in the table below. Real values are right justified in their fields. If the field width is not large enough to accommodate the real number then the field is filled with asterisks. |
print “(f12.3)”,pi |
| E |
This is used for real output in exponential notation. The ‘E’ descriptor statement takes the form ‘rEw.d’ where the meanings of r, w and d are given in the table below. Real values are right justified in their fields. If the field width is not large enough to accommodate the real number then the field is filled with asterisks. Please note that, to print out a real number with three decimal places a field width of at least ten is needed. One for the sign of the mantissa, two for the zero, four for the mantissa and two for the exponent itself. In general, w ≥ d + 7. |
print “(e10.3)”,123456.0 gives ‘0.123e+06’ |
| ES |
This is used for real output (scientific notation). This takes the form ‘rESw.d’ where the meanings of r, w and d are given in the table below. The ‘E’ descriptor described above differs slightly from the traditional well known ‘scientific notation’. Scientific notation has the mantissa in the range 1.0 to 10.0 unlike the E descriptor which has the mantissa in the range 0.1 to 1.0. Real values are right justified in their fields. If the field width is not large enough to accommodate the real number then the field is filled with asterisks. Here also, the width field must satisfy the expressionw ≥ d + 7 |
print “(es10.3)”,123456.0 gives ‘1.235e+05’ |
| A |
This is used for character output. This takes the form ‘rAw’ where the meanings of r and w are given in the table below. Character types are right justified in their fields. If the field width is not large enough to accommodate the character string then the field is filled with the first ‘w’ characters of the string. |
print “(a10)”, str |
| X |
This is used for space output. This takes the form ‘nX’ where ‘n’ is the number of desired spaces. |
print “(5x, a10)”, str |
| / |
Slash descriptor – used to insert blank lines. This takes the form ‘/’ and forces the next data output to be on a new line. |
print “(/,5x, a10)”, str |
以下符号与格式描述符一起使用-
| Sr.No | Symbol & Description |
|---|---|
| 1 |
c Column number |
| 2 |
d Number of digits to right of the decimal place for real input or output |
| 3 |
m Minimum number of digits to be displayed |
| 4 |
n Number of spaces to skip |
| 5 |
r Repeat count – the number of times to use a descriptor or group of descriptors |
| 6 |
w Field width – the number of characters to use for the input or output |
program printPi
pi = 3.141592653589793238
Print "(f6.3)", pi
Print "(f10.7)", pi
Print "(f20.15)", pi
Print "(e16.4)", pi/100
end program printPi
编译并执行上述代码后，将产生以下结果-
3.142
3.1415927
3.141592741012573
0.3142E-01
program printName
implicit none
character (len = 15) :: first_name
print *,' Enter your first name.'
print *,' Up to 20 characters, please'
read *,first_name
print "(1x,a)",first_name
end program printName
编译并执行上述代码后，将产生以下结果：(假定用户输入名称Zara)
Enter your first name.
Up to 20 characters, please
Zara
program formattedPrint
implicit none
real :: c = 1.2786456e-9, d = 0.1234567e3
integer :: n = 300789, k = 45, i = 2
character (len=15) :: str="Tutorials Point"
print "(i6)", k
print "(i6.3)", k
print "(3i10)", n, k, i
print "(i10,i3,i5)", n, k, i
print "(a15)",str
print "(f12.3)", d
print "(e12.4)", c
print '(/,3x,"n = ",i6, 3x, "d = ",f7.4)', n, d
end program formattedPrint
编译并执行上述代码后，将产生以下结果-
45
045
300789 45 2
300789 45 2
Tutorials Point
123.457
0.1279E-08
n = 300789 d = *******
format语句允许您在一个语句中混合和匹配字符，integer和real输出。以下示例演示了这一点-
program productDetails
implicit none
character (len = 15) :: name
integer :: id
real :: weight
name = 'Ardupilot'
id = 1
weight = 0.08
print *,' The product details are'
print 100
100 format (7x,'Name:', 7x, 'Id:', 1x, 'Weight:')
print 200, name, id, weight
200 format(1x, a, 2x, i3, 2x, f5.2)
end program productDetails
编译并执行上述代码后，将产生以下结果-
The product details are
Name: Id: Weight:
Ardupilot 1 0.08