How do I copy a randomly generated array into another array?

Asked Feb 25 '21 at 21:44

Active Feb 25 '21 at 21:45

Viewed 106 times

I want to copy arr into brr so that brr is an exact copy of arr. I think that the main issue is that I am not calculating it right and % 100. How would I do this?

#include <stdio.h>
#include <string.h>  // for using memcpy (library function)

#include <algorithm>
#include <cstdlib>
#include <ctime>
#include <iostream>

using namespace std;

int main() {
  int arr[10];
  int array[10];
  srand((unsigned)time(0));
  for (int i = 0; i < 10; i++) {
    array[i] = (rand() % 10) + 1;
    cout << array[i] << endl;
  }
  int brr[10];
}

edited Feb 25 '21 at 21:45

Aykhan Hagverdili

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asked Feb 25 '21 at 21:44

Tyler Kay

If you take a copy of your current loop, replace array with brr and the random with array you are done? – Surt Feb 25 '21 at 21:46
3

Are you familiar with [`std::copy`](https://en.cppreference.com/w/cpp/algorithm/copy)? – 0x5453 Feb 25 '21 at 21:46
Consider using `std::array` instead of C-style arrays, btw. – Dai Feb 25 '21 at 21:46
Are you familiar with `memcpy`? Seems like you included the commented header, but never used it. – Aykhan Hagverdili Feb 25 '21 at 21:47
Then when you have followed @Dai suggestion, replace `std::array` with `std::vector` – Richard Critten Feb 25 '21 at 21:48
@AyxanHaqverdili yeah, i tried using it but when I do I get these large numbers rather than the copy of the other array – Tyler Kay Feb 25 '21 at 21:49
@TylerKay `memcpy(brr, arr, sizeof(int) * 10);` didn't do the trick? – Aykhan Hagverdili Feb 25 '21 at 21:50
@AyxanHaqverdili the output is a singular memory address – Tyler Kay Feb 25 '21 at 21:53
@TylerKay You need to show the code that doesn't work. We can't guess what you're seeing. – Blastfurnace Feb 25 '21 at 21:53
I also strongly suggest you use `std::copy`, it's easier to use correctly and with plain old data types it will likely compile to a `memmove` and you'll get **very** fast copies. – Blastfurnace Feb 25 '21 at 21:56
@TylerKay see here https://gcc.godbolt.org/z/c5Kn77 – Aykhan Hagverdili Feb 25 '21 at 22:02
@Blastfurnace https://repl.it/@kayt22/CopyArray#main.cpp – Tyler Kay Feb 25 '21 at 22:03
1

@TylerKay `cout << brr;` is not how you print an array. You need a loop like in the snippet I shared. – Aykhan Hagverdili Feb 25 '21 at 22:05

How do I copy a randomly generated array into another array?

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