Lecture 4 - September 6, 2007

Topics discussed

• how to obtain a screen capture of the program output
• how to redirect the input from an input file to a program (to save having to retype input repeatedly as testing program)
• how to redirect the output from a program to an output file (so the output exists after the program is over)
• DOS commands for
• changing drives
• changing directories
• seeing only the folders in a directory
• seeing only the executable files in a directory
• conversion of base 10 fractions to base 2 fractions
• why the base 10 fraction input isn't echoed exactly as read
• use of Blackboard Discussion Board to ask questions about assignments
• submit your questions there
• look at other people's questions and the answers to them to see if your question has already been answerd

Programs discussed in detail and modified in class

10DigitInput

EndEquals

ErrorEquals

Things to remember when writing FORTRAN code

don't embed function calls in a output statement

functions ALWAYS return a value (always exactly 1 value)

when you pass an array into a subprogram, you need to dimension it in the subprogram

the actual parameters you use in a function or subroutine call should be variables not literals

variable names used as formal parameters should match the data type they expect to hold

CHARACTER S(5) declares a five element array

CHARACTER S*5 declares a five character string

<ctrl>z is the end of file character in command mode on a PC

List of some built-in functions in FORTRAN

1) MOD (numerator, denominator) – returns the remainder when numerator is divided by denominator takes real or integer arguments

2) ACHAR(num1) - gives the num^th character in the ASCII collating sequence

3) ABS (number) – the number can be REAL or INTEGER, returns the absolute value of the number

4) MAX (num1, num2) – finds the maximum value in a ______

5) IFIX (REALnumber) – returns a

6) SQRT (integer) – finds the square root – returns a ____

7) LOG (anyTypeNumber) – returns the natural log of x

8) RAND() – returns a random value between 0 and 1 depending on the time clock

9) COS (realNumber) – returns the cosine as a realNumber – the parameter is in radians

10) SIN (realNumber) – returns the sine as a realNumber – the parameter is in radians

11) TAN (realNumber) – returns the tangent as a realNumber – the parameter is in radians

12) SIND(realNumberOfDegrees) – returns an integer which is the truncated real

13) FLOOR (realNumber) – returns as integer which is the truncated real

14) MIN(listOfNumbers) – fins the minimum value in a list of homogeneous type numbers

15) ATAN (realNumber) – returns the inverse of tangent -- returns value in radians

16) CEILING(realNumber) – returns an integer

17) SRAND(integerNumber) – sets the seed for the RAND() function

18) EXP (realNumber) – returns e to the real number power

19) ASIN (realNumber) – returns the inverse of sine -- returns value in radians

20) LEN (string) - length of string

CANDY BAR Questions

If there is a way using Force to have your subroutine or function in a file separate from the main program, what is it? (submit your answer to the Blackboard drop box before next class).