Language Issues

1
Language Issues
Misunderstimated? Sublimable? Hopefuller? "I
know how hard it is for you to put food on your
family. "I know the human being and fish can
coexist peacefully."
2
Outline

• Announcements
• HW1 due Friday
• Developing RAD1D
• Lab

3
Designing RAD1

• Get C0, u, k, dt,t, T, m, L (dxL/(m-1)) from
  user
• Build matrix A using k, dt, dx
• Build RHS vector f using u, k, and reaction data
• Solve ACb for C
• ttdt
• If(tltT)
• Copy CC0
• Change u and k if needed
• Repeat 2-6
• Else
• d) Output C and quit

4
Getting Info From User

• Need several parameter values a file name
• Options
• Query user?
• Values in a file pass file name?
• Cbasic basic.cmnd
• I like option 3

5
Command File

• m--number of grid points
• L--length of the domain
• dt--time step
• T--end time

6
Designing Cbasics

• Get name of command file (user or command line)
• Read command file and get m, L, dt, T
• Create a length m array C
• Fill array with location of grid points
• Save C to C.txt

7
Structure of Cbasics

• Main.c--main program
• Io.c--functions for input/output
• ReadComm
• ReportParams
• PrintArray
• System.c--functions for array allocation error
  reporting
• Error
• newarray_double

8
Prototypes Header files

• C subroutines must declare the types of their
  inputs and outputs using prototypes
• double sin(double angle_in_radians)
• void PrintArray(char name, double C, int m)
• Prototypes allow the compiler to check that you
  are calling a routine in the correct way
• Suppose subroutine X is implemented in file X.c.
  In order to call X from another file (Y.c), Y
  needs to see the prototype for X.
• Solution--create a header file with the prototype
• X.c--implements X
• X.h--prototype for X
• Both X.c and Y.c must include X.h
• include X.h must appear before any call to X
  or its implementation