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計算機程式 C omputer Programming Language Lecture 2 Introduction to Fortran

計算機程式 C omputer Programming Language Lecture 2 Introduction to Fortran. 郭修伯 助理教授 （5488）. Fixed Format. Fortran 77 (*.f /*.for) 欄位： 1 C 為註解 欄位：1-5 為行號 欄位：6 為序接欄位 欄位：7-72 為程式區. Free Format. Fortran 90/95 (*.f90) ! 之後為註解 一行有 132 字元 行號在最前面 & 為連接上一行.

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計算機程式 C omputer Programming Language Lecture 2 Introduction to Fortran

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  1. 計算機程式Computer Programming LanguageLecture 2 Introduction to Fortran 郭修伯 助理教授 （5488）

  2. Fixed Format • Fortran 77 (*.f /*.for) • 欄位：1 • C 為註解 • 欄位：1-5 • 為行號 • 欄位：6 • 為序接欄位 • 欄位：7-72 • 為程式區

  3. Free Format • Fortran 90/95 (*.f90) • ! 之後為註解 • 一行有 132 字元 • 行號在最前面 • & 為連接上一行

  4. A simple program:print a line of text • Fortran 90

  5. A simple program:print a line of text • Fortran 77

  6. A simple program: add two integers • Fortran 90

  7. A simple program: add two integers • Fortran 77

  8. Important issues • 程式前要寫 Comments • Fortran 77 用單引號; Fortran 90 用雙引號 • Fortran programs contain one or more functions, exactly one of which must be main • stopand end • 數學運算式 +, -, *, / ,**, ( )

  9. 簡單的程式結構 program main implicit none integer a,b,c b=1 c=2 a=b+c write (*,*) a stop end

  10. 宣告 • 向電腦要求一塊記錄的記憶體空間 • 用大小寫英文字母、1到9的數字和下橫線；第一個字母必須是字母或數字 • 變數名稱長度 • 77 - 6字元 • 90 - 31字元 • 大小寫字母意義相同 • 不可用 Fortran 的關鍵字 • Integer; Real; Complex; Character; Logical

  11. Integer • 短整數 (2 bytes) -32768 ~ 32768 • Integer*2 a (Fortran 77) • Integer (kind=2) a (Fortran 90) • 長整數 (4 bytes) -2147483648 ~ 2147483648 • Integer a (Fortran 77 & 90) • Interger:: a (Fortran 90) • Integer*4 a (Fortran 77) • Integer (kind=4) a (Fortran 90)

  12. 型態宣告的重要性

  13. Real • 單精準度浮點數 (4 bytes) -3.4e38 ~ 3.4e38 • Real a (Fortran 77 & 90) • Real:: a (Fortran 90) • Real*4 a (Fortran 77) • Real (kind=4) a (Fortran 90) • 雙精準度浮點數 (8 bytes) -1.79e308 ~ 1.79e308 • Double precision a (Fortran 77 & 90) • Real*8 a (Fortran 77) • Real (kind=8) a (Fortran 90)

  14. Complex • 單精準度複數 (4 bytes) -3.4e38 ~ 3.4e38 • Complex a (Fortran 77 & 90) • Complex:: a (Fortran 90) • Complex*4 a (Fortran 77) • Complex (kind=4) a (Fortran 90) • 雙精準度複數 (8 bytes) -1.79e308 ~ 1.79e308 • Complex*8 a (Fortran 77) • Complex (kind=8) a (Fortran 90)

  15. Character • 字串 (？ 字元) • Character*20 a (Fortran 77) • Character(len=20) a (Fortran 90)

  16. Logical • 邏輯變數 • Logical a

  17. READ 輸入資料 • read (*,*) a • read (5,*) a • read (5,100) a • read (unit = 5, fmt = 100) a

  18. More about Format • Refer to textbook 4-4 • A10 • F9.3 • I5 • G9.3 • / • 3X

  19. Implicit • Implicit none • 取消內定型態; 緊接在Program之後

  20. Parameter 設立常數值 • parameter (pi = 3.14159) • Pi = 3.14159; G = 9.81; R = 8.314 … etc. • 避免錯誤 • 增加程式速度

  21. 設定初始值

  22. 型態不同變數運算

  23. Type • integer, real, logical, character 之外的型態宣告

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