fortran主程序和子程序怎么运行主程序_软件运维

FORTRAN程序由一个主程序或一个主程序与若干个子程序组成。主程序与子程序都是一个独立的程序单位，称为一个程序模块。[1]

1、程序分段：一个程序由一个或若干个程序单位组成。主程序和每一个子程序分别是一个独立的程序单位。子程序是实现模块化的有效方法。

2、每一个程序单位都是以“END”语句结束。主程序段中的END语句作用是使程序“停止运行”；子程序段中的END语句是“使流程返回调用程序”。

3、一个程序有且仅有一个主程序段，可以有0个或若干个子程序段。

4、一个程序单位包括若干行。FORTRAN行分为两类：即语句行和非语句行。

其中语句行由一个FORTRAN语句组成。FORTRAN语句又可分为执行语句和非执行语句。非语句行，即为注释行。

5、FORTRAN程序的基本成份是语句。一行只能有一个语句。若一个语句太长，一行内写不下，可分写在几行上，但要用“续行标志”。

6、FORTRAN程序中语句允许有标号，以便被其他句引用。

7一个程序单位中各类语句的位置是有一定规则的。一般是非执行语句放在所有可执行语句之前。[2]

主要使用下面的三个函数实现：

第一个：

COMMAND_ARGUMENT_COUNT — Get number of command line arguments

Description:

COMMAND_ARGUMENT_COUNT returns the number of arguments passed on the command line when the containing program was invoked.

Standard:

Fortran 2003 and later

Class:

Inquiry function

Syntax:

RESULT = COMMAND_ARGUMENT_COUNT()

Arguments:

None

Return value:

The return value is an INTEGER of default kind.

Example:

program test_command_argument_count

integer :: count

count = command_argument_count()

print *, count

end program test_command_argument_count

COMMAND_ARGUMENT_COUNT — Get number of command line arguments

Description:

COMMAND_ARGUMENT_COUNT returns the number of arguments passed on the command line when the containing program was invoked.

Standard:

Fortran 2003 and later

Class:

Inquiry function

Syntax:

RESULT = COMMAND_ARGUMENT_COUNT()

Arguments:

None

Return value:

The return value is an INTEGER of default kind.

Example:

program test_command_argument_count

integer :: count

count = command_argument_count()

print *, count

end program test_command_argument_count

第二个：

GET_COMMAND_ARGUMENT — Get command line arguments

Description:

Retrieve the NUMBER-th argument that was passed on the command line when the containing program was invoked.

Standard:

Fortran 2003 and later

Class:

Subroutine

Syntax:

CALL GET_COMMAND_ARGUMENT(NUMBER [, VALUE, LENGTH, STATUS])

Arguments:

NUMBER Shall be a scalar of type INTEGER and of default kind, NUMBER \geq 0

VALUE (Optional) Shall be a scalar of type CHARACTER and of default kind.

LENGTH (Optional) Shall be a scalar of type INTEGER and of default kind.

STATUS (Optional) Shall be a scalar of type INTEGER and of default kind.

Return value:

After GET_COMMAND_ARGUMENT returns, the VALUE argument holds the

NUMBER-th command line argument. If VALUE can not hold the argument, it

is truncated to fit the length of VALUE. If there are less than NUMBER

arguments specified at the command line, VALUE will be filled with

blanks. If NUMBER = 0, VALUE is set to the name of the program (on

systems that support this feature). The LENGTH argument contains the

length of the NUMBER-th command line argument. If the argument retrieval

fails, STATUS is a positive numberif VALUE contains a truncated

command line argument, STATUS is -1and otherwise the STATUS is zero.

Example:

PROGRAM test_get_command_argument

INTEGER :: i

CHARACTER(len=32) :: arg

i = 0

CALL get_command_argument(i, arg)

IF (LEN_TRIM(arg) == 0) EXIT

WRITE (*,*) TRIM(arg)

i = i+1

END DO

END PROGRAM