diff --git a/hex2hcd.c b/hex2hcd.c
index 0f93937..3da7e68 100644
--- a/hex2hcd.c
+++ b/hex2hcd.c
@@ -19,16 +19,14 @@
 
 #include <stdlib.h>
 #include <stdio.h>
+#include <string.h>
 #include <errno.h>
 
-#define RBUF_SIZE	640
+#define RBUF_SIZE 640
 
 static unsigned int asc_to_int(char a)
 {
-	if (a >= 'A')
-		return (a - 'A') + 10;
-	else
-		return a - '0';
+	return a >= 'A' ? (a - 'A') + 10 : a - '0';
 }
 
 static unsigned int hex_to_int(const char *h)
@@ -60,25 +58,43 @@ static int check_hex_line(const char *str, int len)
 	return 1;
 }
 
+static FILE *open_file(const char *fileName, const char *mode) 
+{
+	FILE *f = fopen(fileName, mode);
+	if (f == NULL) {
+		printf("The file '%s' could not be opened with the following reason\n", fileName);
+        printf("%s\n", strerror(errno));
+        exit(-EIO);
+    }
+    return f;
+}
+
 int main(int argc, char *argv[])
 {
 	unsigned int addr = 0;
+	char *ifn, *ofn;
 	FILE *ifp, *ofp;
 	char *rbuf;
 	ssize_t len, i;
 	size_t buflen;
 
-	if (argc != 3) {
-		printf("Usage: %s <input hex file> <output file>\n", argv[0]);
-		return 0;
+	switch (argc) {
+		case 2:
+			ifn = ofn = argv[1];
+			break;
+		case 3:
+			ifn = argv[1];
+			ofn = argv[2];
+			break;
+		default:
+			printf("Usage: %s <input hex file> [<output file>]\n", argv[0]);
+			return 0;
 	}
 
-	ifp = fopen(argv[1], "r");
-	ofp = fopen(argv[2], "w");
-	if ((ifp == NULL) || (ofp == NULL)) {
-		puts("failed to open file.");
-		return -EIO;
-	}
+
+	ifp = open_file(ifn, "r");
+	ofp = open_file(ofn, "w");
+	
 
 	rbuf = NULL;
 	while ((len = getline(&rbuf, &buflen, ifp)) > 0) {
@@ -94,7 +110,7 @@ int main(int argc, char *argv[])
 		switch (type) {
 			case 4:
 				addr = lhex_to_int(rbuf + 9) * 0x10000;
-				printf("bump addr to 0x%08X\n", addr);
+				printf("Bump addr to 0x%08X\n", addr);
 				break;
 			case 0:
 				dest_addr = addr + lhex_to_int(rbuf + 3);
@@ -109,27 +125,24 @@ int main(int argc, char *argv[])
 					goto output_err;
 				for (i = 0; i < hex_to_int(rbuf + 1); i++) {
 					obuf[0] = hex_to_int(rbuf + 9 + i * 2);
-					if (fwrite(obuf, 1, 1, ofp) != 1)
-						goto output_err;
+					if (fwrite(obuf, 1, 1, ofp) != 1) goto output_err;
 				}
 				break;
 			case 1:
-				if (fwrite("\x4e\xfc\x04\xff\xff\xff\xff", 7, 1, ofp) != 1)
-					goto output_err;
+				if (fwrite("\x4e\xfc\x04\xff\xff\xff\xff", 7, 1, ofp) != 1) goto output_err;
 				goto end;
 			default:
 				return -EINVAL;
 		}
 	}
 
-	puts("hex file formatting error");
+	puts("Hex file formatting error");
 	return -EINVAL;
 
 output_err:
-	puts("error on writing output file");
+	puts("Error on writing output file");
 	return -EIO;
 
-end:
-	return 0;
+end: 
+ 	return 0;
 }
-