NASM x64 read numbers to array and write out - linux

Question

I have got a big problem with reading 10 numbers from keyboard to array and then writing them out.
mov rcx, arr + qword [n]*8 - I don't know how to modify it properly, because actually it causes an error.
Additionally how should I set mov rdx, 1 when I want to read numbers like: 12 123 1234 not only digits?
I would be grateful for any kind of help.
global main
section .text
main:
mov rbp, rsp; for correct debugging
mov rdi, 0
_in:
mov rax, 3
mov rbx, 0
mov rcx, arr + rdi*8
mov rdx, 1
int 80h
mov rax, 3
mov rbx, 0
mov rcx, blank
mov rdx, 1
int 80h
inc qword [n]
cmp qword [n], 10
jz _next
jmp _in
inc rdi
_next:
mov qword [n], 0
mov rdi, 0
_out:
mov rax, 4
mov rbx, 1
mov rcx, arr + rdi*8
mov rdx, 1
int 80h
mov rax, 4
mov rbx, 1
mov rcx, nl
mov rdx, 1
int 80h
inc qword [n]
cmp qword [n], 10
jz _end
jmp _out
inc rdi
_end:
mov rax, 1
mov rbx, 0
ret
section .data
arr times 10 dq 0
blank db 0
n dq 0
nl db 10

Answer 1

About input and data structures.
Keep reading per char (rdx=1), in a loop. Input chars will be for example '1', '2', '3', '4', '5', 10, the character 10 is new line (maybe check also for other whitespace chars like 13, 9, 32 too, or even flip the test, any char out of '0'..'9' range is end of number).
While reading digits, decide if you want to store them as strings, or as numbers.
If strings, then write every new digit into memory at address arr+n*8+input_char_index, put probably zero value as terminator after the number (your current array can hold at most 7 character long strings + zero for each "n"), or store string length into separate array, or as first byte of element, and make first char go at +1 offset after the length byte, etc... (you can design your data structure as you wish). To display such string just load it's address lea rcx,[arr+n*8] and calculate it's length with strlen (it reads+counts char by char until 0 is found), or load the length if you have it stored somewhere, and sys_write it.
If you want to store numbers, set some spare register as zero ahead of input (for example rdi), then for every digit read do add rdi,rdi lea rdi,[rdi+rdi*4] => that's rdi *= 10, then convert the input character from ASCII digit to 64b 0-9 value, and add it to rdi ... loop until non-digit or newline is read (but 64b unsigned number will overflow for 19+ digits input). After end of input store the value into arr, now arr will contain numerical QWORD values.
To output them, you have to do the conversion in opposite direction, from numerical value into some memory buffer, producing digit by digit ASCII characters (have big enough buffer, again 20+ chars is safe for 64b value). After you have your number stored in memory as ASCII string + know it's length, you can SYS_WRITE it to stdout.
You may also consider to follow some more tutorials first and re-read some theory about common data structures/etc, memory, string encodings, registers, x86 addressing modes, .... before writing your own code (as it feels to me that you are guessing a bit too much, how things work).