C source code of immigration-emigration process

• Let's try to compile the code you typed in.

• Programming languages have to be precise, and syntax errors have to be corrected.

• After that, logical flaws need to be corrected.

Explanation

• Comments are anything between /* */

• At the end of each statement, you need semicolon (;)

• White spaces don't matter.
  The following 3 statements means same thing:

  alpha = 0.1;
  alpha          =      0.1         ;
           alpha
        =
  0.1
  ;
  

  But note that the followigs are not;

  n += popSizeIncrement ;   /* correct */
  n += popSize  Increment ; /* syntax error */
  n +  = popSizeIncrement ; /* syntax error, "+='' is one unit */
  

• Any line beginning with # is a command for preprocessor.

  Before the compiler try to understand the source code, pre-processor will execute these commands.

•     #include <library.h>
  • A library is a correction of useful functions, which users can use (No need to reinvent wheels). For example, printf().

  • Header files (libraryName.h) tell the compiler how these functions work, so it can tell if the programmer is using the function correctly.

• #define NAME value
  • #define defines values of symbolic constant. These values get substitued everywhere after precompilation.

  • You can easily change the definition for a later recompilation.

  • Difference between constant and variables.

    You can't assign or change the value of a constant in the program.

        CONST = CONST + 1 ;     /* NOT ALLOWED */

• Every program requires main()