Why it doesnt work correct?

Question

https://code.sololearn.com/clvX8VHYKRFV/?ref=app
when indicate firstly 123 after 456 ,it return 654321,but after a bigger numbers like 45,66,34, it returnes Like(6536544,0,) and oher incorrect numbers

Answer 1

what are you trying to do in the third array?

int r =n/arr1[0];
int arr3[r*2];

Your 'n' and 'arr[0]' are from user inputs.

Answer 2

to merge arra1 and array2 in array3