Example using command line arguments
This example uses command line arguments to give the program the name
of the input file to use and the name of the output file to write during
processing. This is a very common use of command line arguments.
If your program needs command line arguments in order to run, then you should
have a clearly marked useage instructions in your file header comment to
explain how to run the program.
<![CDATA[
#include <stdlib.h>
#include <stdio.h>
main(int argc, char** argv)
{
FILE *ifp, *ofp;
if (argc != 3)
{
printf ("This program requires command line arguments\n");
printf ("that are the name of the input file to be\n");
printf ("used, and the name of the output file to\n");
printf ("be used\n");
exit (-1);
}
ifp = fopen (argv[1], "r");
if (ifp == NULL)
{
printf("Sorry, couldn't open input file:\n");
printf("%s\n", argv[1]);
exit (-2);
}
ofp = fopen (argv[2], "w");
if (ofp == NULL)
{
printf("Sorry, couldn't open output file:\n");
printf("%s\n", argv[2]);
exit (-3);
}
.
.
.
}
]]>
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