converting ints to strings?

What is the completely easiest way to convert an int to a string? I have heard of classes such as stringstream but i am wondering if there is another approach ? (i assume theres nothing like in java, with an integer wrapper class?)

for example what if i wanted to save the string "0" to my array slot 0, and "1" to my array slot 1?

Code:

#include <iostream>
#include <cstring>

using namespace std;

int main()
{
	int sz;
	cin >> sz;
	string *arr = new string[sz];
        //for loop that converts its index to string SOMEHOW(?), and saves it to arr[i]
        for(int i =0 ; i < sz ; ++i)
        {
              arr[i] = i;  //Wrong
              cout << arr[i];
        }
}

thanks!


edit: also thought about that since a string is actually a char pointer array(from what i hear!) that I can just cast a char to an int? is that way?

Originally Posted by rodrigorules

What is the completely easiest way to convert an int to a string? I have heard of classes such as stringstream but i am wondering if there is another approach ?

If I had to rely solely on the standard library, I would indeed use a std::stringstream, e.g.,

Code:

#include <vector>
#include <string>
#include <sstream>
#include <iostream>

using namespace std;

int main()
{
    int sz;
    cin >> sz;
    vector<string> arr(sz);

    // for loop that converts its index to string and saves it to arr[i]
    for (vector<string>::size_type i = 0; i < arr.size(); ++i)
    {
        stringstream ss;
        ss << i;
        ss >> arr[i];
    }

    for (vector<string>::size_type i = 0; i < arr.size(); ++i)
    {
        std::cout << arr[i] << '\n';
    }
    std::cout << std::endl;
}

Notice that instead of dynamically allocating an array and then forgetting to delete[] it, I used a std::vector. This is not Java, so gratuitous use of new and new[] should be avoided.

If I had access to Boost, I might consider using boost::lexical_cast instead (but that actually uses stringstreams to do the job).

Originally Posted by rodrigorules

edit: also thought about that since a string is actually a char pointer array(from what i hear!) that I can just cast a char to an int? is that way?

C-style strings are contiguous sequences of char terminated by a null character, but here you are using std::string objects. Speaking of which, I changed the header included from <cstring> to <string>. Anyway, you cannot just cast a char to int, since that will give you the value of the char, not the int corresponding to the digit.

There's boost::lexical_cast which allows you to do

Code:

int n = 100;
std::string s = boost::lexical_cast<std::string>(100);

However, conversion to string is simpler than the other way round (less chances of failure), so it wouldn't be hard to implement a to_string function for any type supporting operator<< using only standard libraries:

Code:

#include <sstream>
#include <string>

template <class T>
std::string to_string(const T& value)
{
    std::stringstream ss;
    ss << value;
    return ss.str();
}

int main()
{
     int n = 100;
     std::string s = to_string(n);
}