* Fortran Example-1
** Formatting of Fortran77 statements
* One statement per line in general.
** 1. Column-1: the comment indicator:
* C or *
** 2. Column-6: the continuation indicator(any non-blank character) to
* indicate that the current line is the continuation of the
* previous lin when a long statement occupies more than one
C line.
C 3. Columns-2:5 Statement number 1-9999
C 4. Columns-7:72 Statement body
C
* Structure of a program.
* 1. The main program and any number of (external) subprograms.
* 2. They can be placed in any order regardless of call sequence.
* 3. Each program unit (main program and each subprogram) must finish
* with the END statement.
* 4. The main program has no header.
C 5. Each subprogram must start with a header which is either
type function f-name (p1,p2,...,pn)
subroutine s-name (p1,p2,...,pk)
C Until Fortran90, it did not have
* a. recursion
* b. pointers
* c. Derived types such as records
* d. case (multiple selections)
* exit (premature loop termination) like 'break' of java/C++
* cycle (transfer control to the bottom of a loop)
* like 'continue' of Java.
* e. Some matrix functions:
** Dot_Product
** MatMul
** transpose
** Sum
** MaxVal and MinVal
****************************************************
! Some Major Changes of Fortran90
! 1. Free source form (No Source formatting)
! a. No special designated column positions like C-1 or C-6
! b. '&' appearing at the end of a line is to indicate that
! the next line is a continuation line.
! c. A line now has 132 positions.
! d. Multiple statements on a line when separated by ';'
! as in: X=X+1; Call Sub(A,B); X=MatMul(Y,Z)
! 2. A new program unit: Module
! It can be used for specifying global data types (possibly derived)
! and variables and subprograms which other program units can access
! with the use of 'USE' statement which should be the first
! specification statement of any program unit.
! 3. Separation of external subprograms from internal subprograms.
! 4. The main program, each external subprogram (not contained in
! any other program unit) can have any number of internal
! subprograms. Each module can have any number of module subprograms
! and each module subprogram can have any number of internal subprograms.
! No internal subprogram can have any further (internal) subprogram.
! That is, the max nesting level of internal subprograms is just one.
! 5. Array expressions.
! Arrays can appear in many expressions just like a scalar.
! ArrayB = ArrayA + 1.0
! ArrX = ArrY * ArrZ
! ArrX(:, K:L) = ArrY(M, :, K+2:L+2)
! ArrX = Transpose(ArrY)
! ArrX = MatMul(ArrA, ArrB)
! 6. Recursive functions
Recursive integer Function Fact(N) RESULT(Fa)
! RESULT Clause is needed as the function name is to be used
! in recursive calls and hence is not to be used in calculating
! the function value. 'Fa' is to be used for this latter purpose.
integer N, Fa
Fa=1
If (N .LE. 1) Return
Fa = N * Fact(N-1)
End function Fact
C COSC3308 FORTRAN EXAMPLE-1
C Combination Calculation
C
Subroutine Printing
Integer Comb(300,9), Many, Count
Common Comb, Many, Count
C Subroutine body follows
write (99,105) Many, count !!! create a data file named FOR099.DAT
100 Format ('1# of values==', I4 /'0# of combinations==', I4/)
105 Format (' # OF VALUES==', I4 /' # OF COMBINATIONS==', I4/)
Do 200 i = 1, Count
write(99, 300) ( comb(i,j), j=1, many)
** Write (6, 300) ( Comb(i,j), j=1,Many)
300 FORMAT (' ', 9I4)
200 Continue
End ! End of subroutine Printing
Subroutine Combinations
C CALCULATING COMBINATIONS OF NUMBERS, UP TO 9 NUMBERS
C
IMPLICIT INTEGER (A-Z)
INTEGER COMB(300,9)
LOGICAL MORE
COMMON COMB,MANY,COUNT
COUNT=1
DO 100 M=1, MANY
100 COMB(COUNT,M)=M ! THE FIRST COMBINATION: 1,2,3,...,MANY
C
C SET UP AN INFINITE LOOP IN WHICH TO PICK UP THE NEXT COMBINATION
C
MORE = .TRUE.
DO WHILE (MORE)
MORE= .FALSE. !!! ASSUME THAT NO MORE COMBINATION IS TO BE FOUND !!!
DO 200 M=MANY,1,-1
IF (COMB(COUNT,M) .LT. 9-MANY+M) Then
MORE = .true.
Last = M
exit
End if
200 CONTINUE
IF (MORE) THEN
COUNT=COUNT+1
DO 500 N=1, Last-1
500 COMB(COUNT,N)=COMB(COUNT-1,N)
KEEP=COMB(COUNT-1,Last)
DO 600 N=Last,MANY
KEEP=KEEP+1
600 COMB(COUNT,N) = KEEP
END IF ! END OF IF (MORE)
END DO ! END OF THE INFINITE LOOP !!!!!!!!!!!!!
RETURN
END
CCC Main program left out for you to figure out.
CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
CCC Outputs of the program
# OF VALUES== 2
# OF COMBINATIONS== 36
1 2
1 3
1 4
1 5
1 6
1 7
1 8
1 9
2 3
2 4
2 5
2 6
2 7
2 8
2 9
3 4
3 5
3 6
3 7
3 8
3 9
4 5
4 6
4 7
4 8
4 9
5 6
5 7
5 8
5 9
6 7
6 8
6 9
7 8
7 9
8 9
# OF VALUES== 3
# OF COMBINATIONS== 84
1 2 3
1 2 4
1 2 5
1 2 6
1 2 7
1 2 8
1 2 9
1 3 4
1 3 5
1 3 6
1 3 7
1 3 8
1 3 9
1 4 5
1 4 6
1 4 7
1 4 8
1 4 9
1 5 6
1 5 7
1 5 8
1 5 9
1 6 7
1 6 8
1 6 9
1 7 8
1 7 9
1 8 9
2 3 4
2 3 5
2 3 6
2 3 7
2 3 8
2 3 9
2 4 5
2 4 6
2 4 7
2 4 8
2 4 9
2 5 6
2 5 7
2 5 8
2 5 9
2 6 7
2 6 8
2 6 9
2 7 8
2 7 9
2 8 9
3 4 5
3 4 6
3 4 7
3 4 8
3 4 9
3 5 6
3 5 7
3 5 8
3 5 9
3 6 7
3 6 8
3 6 9
3 7 8
3 7 9
3 8 9
4 5 6
4 5 7
4 5 8
4 5 9
4 6 7
4 6 8
4 6 9
4 7 8
4 7 9
4 8 9
5 6 7
5 6 8
5 6 9
5 7 8
5 7 9
5 8 9
6 7 8
6 7 9
6 8 9
7 8 9
# OF VALUES== 4
# OF COMBINATIONS== 126
1 2 3 4
1 2 3 5
1 2 3 6
1 2 3 7
1 2 3 8
1 2 3 9
1 2 4 5
1 2 4 6
1 2 4 7
1 2 4 8
1 2 4 9
1 2 5 6
1 2 5 7
1 2 5 8
1 2 5 9
1 2 6 7
1 2 6 8
1 2 6 9
1 2 7 8
1 2 7 9
1 2 8 9
1 3 4 5
1 3 4 6
1 3 4 7
1 3 4 8
1 3 4 9
1 3 5 6
1 3 5 7
1 3 5 8
1 3 5 9
1 3 6 7
1 3 6 8
1 3 6 9
1 3 7 8
1 3 7 9
1 3 8 9
1 4 5 6
1 4 5 7
1 4 5 8
1 4 5 9
1 4 6 7
1 4 6 8
1 4 6 9
1 4 7 8
1 4 7 9
1 4 8 9
1 5 6 7
1 5 6 8
1 5 6 9
1 5 7 8
1 5 7 9
1 5 8 9
1 6 7 8
1 6 7 9
1 6 8 9
1 7 8 9
2 3 4 5
2 3 4 6
2 3 4 7
2 3 4 8
2 3 4 9
2 3 5 6
2 3 5 7
2 3 5 8
2 3 5 9
2 3 6 7
2 3 6 8
2 3 6 9
2 3 7 8
2 3 7 9
2 3 8 9
2 4 5 6
2 4 5 7
2 4 5 8
2 4 5 9
2 4 6 7
2 4 6 8
2 4 6 9
2 4 7 8
2 4 7 9
2 4 8 9
2 5 6 7
2 5 6 8
2 5 6 9
2 5 7 8
2 5 7 9
2 5 8 9
2 6 7 8
2 6 7 9
2 6 8 9
2 7 8 9
3 4 5 6
3 4 5 7
3 4 5 8
3 4 5 9
3 4 6 7
3 4 6 8
3 4 6 9
3 4 7 8
3 4 7 9
3 4 8 9
3 5 6 7
3 5 6 8
3 5 6 9
3 5 7 8
3 5 7 9
3 5 8 9
3 6 7 8
3 6 7 9
3 6 8 9
3 7 8 9
4 5 6 7
4 5 6 8
4 5 6 9
4 5 7 8
4 5 7 9
4 5 8 9
4 6 7 8
4 6 7 9
4 6 8 9
4 7 8 9
5 6 7 8
5 6 7 9
5 6 8 9
5 7 8 9
6 7 8 9
# OF VALUES== 5
# OF COMBINATIONS== 126
1 2 3 4 5
1 2 3 4 6
1 2 3 4 7
1 2 3 4 8
1 2 3 4 9
1 2 3 5 6
1 2 3 5 7
1 2 3 5 8
1 2 3 5 9
1 2 3 6 7
1 2 3 6 8
1 2 3 6 9
1 2 3 7 8
1 2 3 7 9
1 2 3 8 9
1 2 4 5 6
1 2 4 5 7
1 2 4 5 8
1 2 4 5 9
1 2 4 6 7
1 2 4 6 8
1 2 4 6 9
1 2 4 7 8
1 2 4 7 9
1 2 4 8 9
1 2 5 6 7
1 2 5 6 8
1 2 5 6 9
1 2 5 7 8
1 2 5 7 9
1 2 5 8 9
1 2 6 7 8
1 2 6 7 9
1 2 6 8 9
1 2 7 8 9
1 3 4 5 6
1 3 4 5 7
1 3 4 5 8
1 3 4 5 9
1 3 4 6 7
1 3 4 6 8
1 3 4 6 9
1 3 4 7 8
1 3 4 7 9
1 3 4 8 9
1 3 5 6 7
1 3 5 6 8
1 3 5 6 9
1 3 5 7 8
1 3 5 7 9
1 3 5 8 9
1 3 6 7 8
1 3 6 7 9
1 3 6 8 9
1 3 7 8 9
1 4 5 6 7
1 4 5 6 8
1 4 5 6 9
1 4 5 7 8
1 4 5 7 9
1 4 5 8 9
1 4 6 7 8
1 4 6 7 9
1 4 6 8 9
1 4 7 8 9
1 5 6 7 8
1 5 6 7 9
1 5 6 8 9
1 5 7 8 9
1 6 7 8 9
2 3 4 5 6
2 3 4 5 7
2 3 4 5 8
2 3 4 5 9
2 3 4 6 7
2 3 4 6 8
2 3 4 6 9
2 3 4 7 8
2 3 4 7 9
2 3 4 8 9
2 3 5 6 7
2 3 5 6 8
2 3 5 6 9
2 3 5 7 8
2 3 5 7 9
2 3 5 8 9
2 3 6 7 8
2 3 6 7 9
2 3 6 8 9
2 3 7 8 9
2 4 5 6 7
2 4 5 6 8
2 4 5 6 9
2 4 5 7 8
2 4 5 7 9
2 4 5 8 9
2 4 6 7 8
2 4 6 7 9
2 4 6 8 9
2 4 7 8 9
2 5 6 7 8
2 5 6 7 9
2 5 6 8 9
2 5 7 8 9
2 6 7 8 9
3 4 5 6 7
3 4 5 6 8
3 4 5 6 9
3 4 5 7 8
3 4 5 7 9
3 4 5 8 9
3 4 6 7 8
3 4 6 7 9
3 4 6 8 9
3 4 7 8 9
3 5 6 7 8
3 5 6 7 9
3 5 6 8 9
3 5 7 8 9
3 6 7 8 9
4 5 6 7 8
4 5 6 7 9
4 5 6 8 9
4 5 7 8 9
4 6 7 8 9
5 6 7 8 9
# OF VALUES== 6
# OF COMBINATIONS== 84
1 2 3 4 5 6
1 2 3 4 5 7
1 2 3 4 5 8
1 2 3 4 5 9
1 2 3 4 6 7
1 2 3 4 6 8
1 2 3 4 6 9
1 2 3 4 7 8
1 2 3 4 7 9
1 2 3 4 8 9
1 2 3 5 6 7
1 2 3 5 6 8
1 2 3 5 6 9
1 2 3 5 7 8
1 2 3 5 7 9
1 2 3 5 8 9
1 2 3 6 7 8
1 2 3 6 7 9
1 2 3 6 8 9
1 2 3 7 8 9
1 2 4 5 6 7
1 2 4 5 6 8
1 2 4 5 6 9
1 2 4 5 7 8
1 2 4 5 7 9
1 2 4 5 8 9
1 2 4 6 7 8
1 2 4 6 7 9
1 2 4 6 8 9
1 2 4 7 8 9
1 2 5 6 7 8
1 2 5 6 7 9
1 2 5 6 8 9
1 2 5 7 8 9
1 2 6 7 8 9
1 3 4 5 6 7
1 3 4 5 6 8
1 3 4 5 6 9
1 3 4 5 7 8
1 3 4 5 7 9
1 3 4 5 8 9
1 3 4 6 7 8
1 3 4 6 7 9
1 3 4 6 8 9
1 3 4 7 8 9
1 3 5 6 7 8
1 3 5 6 7 9
1 3 5 6 8 9
1 3 5 7 8 9
1 3 6 7 8 9
1 4 5 6 7 8
1 4 5 6 7 9
1 4 5 6 8 9
1 4 5 7 8 9
1 4 6 7 8 9
1 5 6 7 8 9
2 3 4 5 6 7
2 3 4 5 6 8
2 3 4 5 6 9
2 3 4 5 7 8
2 3 4 5 7 9
2 3 4 5 8 9
2 3 4 6 7 8
2 3 4 6 7 9
2 3 4 6 8 9
2 3 4 7 8 9
2 3 5 6 7 8
2 3 5 6 7 9
2 3 5 6 8 9
2 3 5 7 8 9
2 3 6 7 8 9
2 4 5 6 7 8
2 4 5 6 7 9
2 4 5 6 8 9
2 4 5 7 8 9
2 4 6 7 8 9
2 5 6 7 8 9
3 4 5 6 7 8
3 4 5 6 7 9
3 4 5 6 8 9
3 4 5 7 8 9
3 4 6 7 8 9
3 5 6 7 8 9
4 5 6 7 8 9