You did not have stdlib.

You need to include both stdio to get printf and stdlib to get exit.

C has a very small set of functions built in.  You can add in all kinds of
additional functionality.  In order to do that, you need to add the
headers.  Those headers are collected together in the header files.

C has an exit function that is defined, but is not really defined for use.
Standard Lib redefines the exit command you used.  Without that header, the
prototype of the exit command as defined and as used did not match.  By
adding the header at the top, the use and.prototype are now in sync and the
program compiles.

Good Luck
Kevin
On Dec 19, 2011 11:05 PM, "Michael Havens" <bmike1@gmail.com> wrote:

> so please, do share.... why wouldn't my version compile?
>
>
>>  > On Mon, Dec 19, 2011 at 4:04 PM, Kevin Fries <kevin@fries-biro.com>
>> wrote:
>> >>
>> >> kfries@kfries-laptop:tmp$ cat ex2.c
>> >> #include <stdio.h>
>> >> #include <stdlib.h>
>> >>
>> >> int main (int argc, char **argv) {
>> >>   int argcount = 1;
>> >>   int mode;
>> >>
>> >>   while (argcount < argc) {
>> >>      if (strcmp(argv[argcount], "-mode1") == 0) {
>> >>         argcount++;
>> >>         printf("Mode 1 Parameter = %s\n", argv[argcount++]);
>> >>         mode = 1;
>> >>      } else if (strcmp(argv[argcount], "-mode2") == 0) {
>> >>         argcount++;
>> >>         printf("Mode 2 Parameter = %s\n", argv[argcount++]);
>> >>         mode = 2;
>> >>      } else {
>> >>         printf("Unknown command %s\n", argv[argcount]);
>> >>         exit(1);
>> >>      }
>> >>   }
>> >>
>> >>   printf("End of program in mode %d\n", mode);
>> >> }
>> >>
>> >>
>> >> kfries@kfries-laptop:tmp$ gcc -o ex2 ex2.c
>> >> kfries@kfries-laptop:tmp$ ./ex2 -mode1 hello
>> >> Mode 1 Parameter = hello
>> >> End of program in mode 1
>> >> kfries@kfries-laptop:tmp$ ./ex2 -mode2 world
>> >> Mode 2 Parameter = world
>> >> End of program in mode 2
>> >> kfries@kfries-laptop:tmp$ ./ex2 -mode3 foobar
>> >> Unknown command -mode3
>> >> kfries@kfries-laptop:tmp$
>> >>
>> >>
>> >>
>> >> Kevin Fries
>> >>
>> >>
>> >>
>> >> On Mon, 2011-12-19 at 15:48 -0700, Michael Havens wrote:
>> >> > #include <stdio.h>
>> >> > int main (int argc, char * argv[])
>> >> > {
>> >> > int argcount=1; /* argv 1 is the first parameter */
>> >> > int mode;
>> >> > while(argcount < argc )
>> >> >     {
>> >> >     if(strcmp(argv[argcount],"-mode1") == 0)
>> >> >         {
>> >> >         argcount++;
>> >> >         printf("mode 1 parameter = %s\n",argv[argcount ++]);
>> >> >         mode =1;
>> >> >         }
>> >> >     else if (strcmp(argv[argcount],"-mode2") == 0)
>> >> >         {
>> >> >         argcount++;
>> >> >         printf("mode 2 parameter = %s\n",argv[argcount ++]);
>> >> >         mode =2;
>> >> >         }
>> >> >     else if(strcmp(argv[argcount],"-help") == 0)
>> >> >         {
>> >> >         argcount++;
>> >> >         printf("Help mode\n");
>> >> >         }
>> >> >     else
>> >> >         {
>> >> >         printf("unknown command %s\n",argv[argcount]);
>> >> >         exit(1);
>> >> >         }
>> >> >     }
>> >> > printf("end of program in mode %d\n",mode);
>> >> > }
>> >>
>> >> ---------------------------------------------------
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>> >
>> >
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>
>
>
> --
> :-)~MIKE~(-:
>
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