Address of C++ local variable is before the address returned by gdb info frame locals

I have the following source code (in a file named vuln.cpp) in C:

#include <stdio.h>#include <string.h>int main(int argc, char ** argv){    char real[20];    char pass[20] = "dddddddddddddddd";    if(argc < 2)    {        printf("Usage:\t%s\tpassword\n", argv[0]);        return -1;    }    memcpy(real, argv[1], strlen(argv[1]) + 1);    if(strncmp(real, pass, 20) == 0)    {        printf("SUCCESS!\n");    }    else    {        printf("FAILURE!\n");    }    printf("real:\t%s\npass:\t%s", real, pass);    return 0;}

I compiled the source code using gcc -g -O0 vuln.cpp. Note that my machine as well as OS (Ubuntu 18.04) has x86_64 architecture

I ran gdb a.out, then b 16, then run $(python -c 'print("a"*10)')

Now with the code running at line 16, just after the memcpy, I do info frame. This outputs

(gdb) info frameStack level 0, frame at 0x7fffffffd9d0: rip = 0x555555554887 in main (vuln.cpp:17); saved rip = 0x7ffff7a05b97 source language c++. Arglist at 0x7fffffffd9c0, args: argc=2, argv=0x7fffffffdaa8 Locals at 0x7fffffffd9c0, Previous frame's sp is 0x7fffffffd9d0 Saved registers:  rbp at 0x7fffffffd9c0, rip at 0x7fffffffd9c8

Now I did p &real

$3 = (char (*)[20]) 0x7fffffffd980

How can the address of the local variable real[0] be before the address of locals listed in the info frame?