Hexdump: add check if file exists

src/hexdump.c

@@ -63,6 +63,10 @@ int main() {
 	char data[10000]; // FIXME
 	char ch;
 	int byte = 0; // FIXME
+	if (infile == NULL) {
+		printf("Cannot find file: \n");
+		return 0;
+	}
 	while ((ch = fgetc(infile)) != EOF)
         {
             data[byte] = ch;