/*
 * Simple program to copy file, character by character.  
 * Uses command-line arguments to specify filenames.
 */
#include <stdio.h>

int main(int argc, char* argv[]) {
	/* 
	 * check that user supplied two arguments 
	 * by convention argv[0] is something that identifies the
	 * program (often its filename -- e.g., a.out).
	 */
	if (argc != 3) {
		printf("usage %s infile outfile\n", argv[0]);
		return 1;
	}
	/* 
	 * open input, output files -- note that fopen returns NULL if it 
	 * could not do this, e.g., input file not found.
	 */
	FILE * infile = fopen(argv[1], "r");
	if (infile == NULL) {
		printf("could not open input file %s\n", argv[1]);
		return 1;
	}
	FILE * outfile = fopen(argv[2], "w");
	if (outfile == NULL) {
		printf("could not open output file %s\n", argv[2]);
		return 1;
	}
	/* copy infile to outfile -- compare to copy.c */
	int inchar;
	while ((inchar = fgetc(infile)) != EOF) {
		fputc(inchar, outfile);
	}
	/*
	 * close files -- free up system resources, make sure all of
	 * output file is actually written to disk
	 */
	fclose(infile);
	fclose(outfile);

	return 0;
}