+ 1

Please someone tell me how to allocate memory to an integer array dynamically without specifying it's size (i.e.not arr [5])

the size of an array must be known only at runtime( should depend on user). I tried out this while(cin>>n) { arr [i++]=n; } but I don't think that the above code is correct please if someone finds the correct ping me so that let me know. thank you

19th Jun 2018, 8:24 PM
Sabitha
5 ответов
+ 3
Your best bet would be using the vector template class. It can grow or shrink as needed. http://en.cppreference.com/w/cpp/container/vector
20th Jun 2018, 12:54 AM
John Wells
John Wells - avatar
+ 1
Also it would be much helpful if you provide some other better solution
19th Jun 2018, 8:25 PM
Sabitha
0
you need to know how big the array must be, so you can allocate the memory needed for it. so your user could for example input a size n and you could use malloc to allocate the appropriate size(i‘m assuming we are talking about c in c++ you of course have to use new). you can not dynamically change the size of an array. if you need that you should use a linked list or another datastructure that can handle dynamic changes of size. so in c++ for example you can do: cin >>n; int *array = new int[n]; to create an array of user specified size if you do not want to specify a size on creation you can use vector or similar datastructures in c++
19th Jun 2018, 9:17 PM
Max
Max - avatar
0
i dont know c++ but could you use an arraylist. in java an arraylist is an array class where if it runs out of space it creates a new array that is twice as big and “copies” the values from the old array to the new array in order. thus it has more space i dont know if that translates to c++ and if it does it still may not work in this case
19th Jun 2018, 10:39 PM
Winston Summers
Winston Summers - avatar
0
thank you so much for all those who replied me.
21st Jun 2018, 2:47 PM
Sabitha