Question: Hi guys i am new to c++, I just wrote this code to find min/max of a array of numbers.  

I just want to know how can I make the no. of entries flexible(I mean the user should be able to enter as many entries as possible without specifying how many in the starting)

Here's the code, but its not working, can someone please help?
Thanks
code:

```
#include <iostream>
using namespace std;
int main(){

    cout<<"Program to calculate max/min/second max\n";
    int *A;
    A=new int[5];
    bool flag=false;
    int x=0,i=0;
    cout<<"Enter the numbers\n";

    do{

        cin>>x;
        if(x=='\0'){
            flag=true;
        }
        *(A+i)=x;
        i++;

    }
    while(!flag);

    for(int j=0;j<i;j++){

        cout<<*(A+j)<<"\n";

    }

    return 0;
}

```

Answer: 
Dynamic Memory Allocation is a bit of a tricky subject for a beginning programmer (in C and C++ in any case.) The easiest way is to have the user specify how many entries, but you don't want this.

Otherwise using the vector class over an array is probably a better (and easier to grapple with than directly using pointers.)

<http://www.cplusplus.com/reference/stl/vector/> is a good place to start. Look at the syntax for creating the vector and the `push_back()` member function to accomplish your task.

Good Luck,

SegFaults McGee
If you use

```
std::vector<int> a;

```

then the input becomes simply

```
while (std::cin >> x)
    a.push_back(x);

```

Then the user can press ^D (Unix/Linux/etc) or ^Z (DOS/Win) when they've entered all the numbers, or use the program as in: 

```
echo 1 4 22 | program
program < input_file

```

If you want to have an empty line denote the end of input, then with input validation:

```
std::string line;
while (getline(std::cin, line))
{
    char c;
    std::istringstream iss(line);
    int x;
    if (iss >> x)
    {
        a.push_back(x);
        char c;
        if (iss >> c)
        {
            std::cerr << "unexpected character '" << c << "' in line '" << line << "', terminating\n";
            exit(EXIT_FAILURE);
        }
    }
    else if (!iss.eof())
        break;  // empty line...
    else
    {
        std::cerr << "unexpected characters in line '" << line << "', terminating\n";
        exit(EXIT_FAILURE);
    }
}

```