Converting cmd arg to int

I am trying to convert the first command argument from char ** to an int i can use to declare an array, but I can't figure out how to do it. Basically that user specifies the size of the array from that cmd argument.

example: person puts 10 in command argument

Code:

---

int main(int argc, char **argv)
{

    //code here to make an:
    int iArray[argv[1](or whatever) that works as int=10 or any cmd line argument] ] = {0};

}

---

I've tried a bunch of things like reinterpret_cast etc but all i can get is a bunch of random values in my int :(

You can use atoi( ) to convert a string to an int.

Also, you're going to need to dynamically allocate the array. You can't do it the way you are right now.

You don't want the compiler to pretend that a string is an int, you want to actually take the int represented by the string and use it as an int. To do this you need to do a real conversion:

Code:

---

// With atoi
#include <stdlib.h>
...
int i = atoi ( argv[1] );

---

Code:

---

// With strtol because atoi sucks
#include <cstdlib>
...
int i = static_cast<int> ( strtol ( argv[1], 0, 0 );

---

Code:

---

// With stringstreams because they're cool :)
#include <sstream>
...
stringstream ss ( argv[1] );
int i;

ss>> i;

---

Or you could do it manually, but that's tricky and I don't recommend it unless you're in learning mode.

>int iArray[ /* Something */ ] = {0};
This isn't legal C++. You would be declaring an array with a non-constant size. While such a feature is a common extension, it isn't standard. You'll need to either declare a dynamic array:

Code:

---

// Assuming i was suitably initialized
int *iArray = new int[i];

---

Or use a standard vector:

Code:

---

#include <vector>
...
// Assuming i was suitably initialized
vector<int> iArray ( i );

---

[edit]
I'm officially embarrassed...
[/edit]

>#include <stdlib.h>
You're really starting to worry me, Prelude... we may have to find a new coding guru.

Oh, and just a quick note to the OP: for Prelude's last two examples, you need to put 'using namespace std;' at the top of your code, just below the #includes.

>You're really starting to worry me, Prelude... we may have to find a new coding guru.
Two goofs in less than an hour worries me as well. :p

thanks, it works like a charm now :)