implement main function to initialize CPU and memory, and print CPU state

src/main.c

@@ -0,0 +1,15 @@
+#include <stdio.h>
+#include "cpu.h"
+#include "memory.h"
+int main()
+{
+    CPU6502 cpu;
+    Memory mem;
+
+    mem_reset(&mem);
+    cpu_reset(&cpu);
+
+    cpu_print_state(&cpu);
+
+    return 0;
+}