1 / 10

Understanding Functions in Programming

Learn how to efficiently use subprograms, functions, and intrinsic functions to simplify code and enhance functionality in programming. Includes examples and exercises.

jsommers
Download Presentation

Understanding Functions in Programming

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. LAB-06IF + Functions I Putu Danu Raharja raharja @kfupm.edu.sa Information & Computer Science Department CCSE - King Fahd University of Petroleum & Minerals

  2. Rationale • If you work on a program to solve a bigger problem, your program will become larger (more lines of code). • A large program is harder to debug (so far we have written programs < 100 lines but we still make mistakes) • Some of the code may be used several times.

  3. Subprogram • A big problem can be solved by dividing it into smaller sub-problems and conquering the sub-problems • A large program can be divided into simpler sub-programs that can be implemented and tested independently • Sub-programs can be reused

  4. Terminologies • Main program • Sub-program • Call & return • Function • Subroutine

  5. Function • A function consists of: • Function header • Function body • Function header type FUNCTION fname (list of arguments) • Function body • Declaration statements • Executable statements • Must have at least one RETURN statement • Must be ended with an END statement

  6. Example: Area of a triangle REAL FUNCTION TRAREA (A, B) REAL A, B TRAREA = A * B / 2 RETURN END REAL X, Y, AREA READ*, X, Y AREA = TRAREA(X, Y) PRINT*, 'Area = ', AREA END

  7. Intrinsic Functions • Functions which are available from the FORTRAN language (p. 63)

  8. Statement Function • Expressed as: fname (list of arguments) = expression • Example: TRA (BASE, HEIGHT) = BASE * HEIGHT * 0.5

  9. Exercises • A year with 366 days is called a leap year. A year is a leap year if it is divisible by 4 (for example, 1980), except that it is not a leap year if it is divisible by 100 (for example, 1900); however, it is a leap year if it is divisible by 400 (for example, 2000). There were no exceptions before the introduction of the Gregorian calendar on October 15, 1582 (for example, 1500 was a leap year). Write a logical function to determine whether the given year is a leap year.

  10. Exercise • Write a function that takes month and year as arguments and returns the number of days of that month. • Write a function that takes two real numbers and tests whether they are the same up to two decimal places. • Write a function that takes two times (hour and minute) in military format (09:00, 17:30) and computes the number of hours between the two times. You have to consider the case that the first time is later than the second time.

More Related