diff --git a/main.c b/main.c
index c3ce445..8118cff 100644
--- a/main.c
+++ b/main.c
@@ -1,7 +1,89 @@
+#include "record.h"
 #include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
 
-int main()
+#define MAX_RECORDS 1000
+#define END_PROGRAM -1
+#define SUCCESS 0
+#define ERROR -2
+
+void print_usage()
 {
-    printf("Hello World\n");
-    return 0;
+    printf("Usage: [-f filename] [-h]\n");
+    printf("Options:\n");
+    printf("  -f filename\tRead records from file\n");
+    printf("  -h\tShow this help message");
+}
+
+// stream is function output
+int process_args(int argc, char** argv, FILE** stream)
+{
+    char* filename = NULL;
+    int opt;
+    while ((opt = getopt(argc, argv, "f:h")) != -1) {
+        switch (opt) {
+        case 'f':
+            filename = optarg;
+            break;
+        case 'h':
+            print_usage();
+            return END_PROGRAM;
+        case '?':
+            printf("invalid option, terminating\n");
+            return ERROR;
+        }
+    }
+    if (filename != NULL) {
+        printf("%s\n", filename);
+        *stream = fopen(filename, "r");
+        if (!*stream) {
+            fprintf(stderr, "Error: Cannot open file '%s'\n", filename);
+            return END_PROGRAM;
+        }
+    }
+    return SUCCESS;
+}
+
+void process_input(FILE* input)
+{
+    record records[MAX_RECORDS];
+    int count = 0;
+    while (count < MAX_RECORDS) {
+        if (read_record(input, &records[count]) != SUCCESS) {
+            break;
+        }
+        count++;
+    }
+
+    printf("\nRead %d records\n", count);
+    qsort(records, count, sizeof(record), compare_records);
+    printf("\nSorted records:\n");
+    for (int i = 0; i < count; i++) {
+        printf("Record %d: ", i);
+        print_record(stdout, &records[i]);
+        printf("\n");
+    }
+}
+
+int main(int argc, char** argv)
+{
+    FILE* input = NULL;
+    if (argc > 1) {
+        int result = process_args(argc, argv, &input);
+        if (result != SUCCESS) {
+            return result;
+        }
+        if (input == NULL) {
+            printf("ok\n");
+        }
+    }
+    if (input == NULL) {
+        printf("Enter records (format: a_0 a_1 a_2 a_3 a_4 x), or 'q' to quit:\n");
+        input = stdin;
+    }
+    process_input(input);
+    if (input != stdin) {
+        fclose(input);
+    }
 }
diff --git a/record.h b/record.h
index 1eec490..89dc0e0 100644
--- a/record.h
+++ b/record.h
@@ -6,18 +6,6 @@ typedef struct {
     int x;
 } record;
 
-static inline int read_record(FILE* stream, record* out)
-{
-    int result = fscanf(stream, "%d %d %d %d %d %d", &out->a[0], &out->a[1], &out->a[2], &out->a[3], &out->a[4], &out->x);
-    if (result == 6) {
-        return 0;
-    }
-    if (result == EOF) {
-        return EOF;
-    }
-    return -2;
-}
-
 static inline int g(const record* x)
 {
     int out = 0;
@@ -37,3 +25,21 @@ static inline int compare_records(const void* a, const void* b)
     const int gb = g(rb);
     return (ga > gb) - (ga < gb);
 }
+
+static inline void print_record(FILE* stream, const record* out)
+{
+    fprintf(stream, "[%d %d %d %d %d] x=%d, g=%d",
+        out->a[0], out->a[1], out->a[2], out->a[3], out->a[4], out->x, g(out));
+}
+
+static inline int read_record(FILE* stream, record* out)
+{
+    int result = fscanf(stream, "%d %d %d %d %d %d", &out->a[0], &out->a[1], &out->a[2], &out->a[3], &out->a[4], &out->x);
+    if (result == 6) {
+        return 0;
+    }
+    if (result == EOF) {
+        return EOF;
+    }
+    return -2;
+}
diff --git a/tests/1.in b/tests/1.in
new file mode 100644
index 0000000..062d8c2
--- /dev/null
+++ b/tests/1.in
@@ -0,0 +1,6 @@
+12312 312312 312 312 323 3
+543 3435 34 5342 532 54
+344 43534 222 435 2345 23
+2345 234 23423 455 44 4
+2345 23222 222 2245 4554 10
+2345 22 2 22 2 3