Question

Possible Duplicate:
How do I create a random alpha-numeric string in C++?

I need to create a 6 digit number. What should I use? Can someone give me a c++ code example?

This is my code: (once in a while the number is repeating)

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <iostream>
using namespace std;
int
main (int argc, char *argv[])
{
  /* Simple "srand()" seed: just use "time()" */
  unsigned int iseed = (unsigned int)time(NULL);
  srand (iseed);

  /* Now generate 5 pseudo-random numbers */
  int i;
  bool da=false;
  while (da==false)
  {if (rand ()%1000000<=999999)
  {cout<<"random nr: "<<rand ()%1000000<<endl;
  da=true;
}
else da=false;
}
 /* for (i=0; i<5; i++)
  {
    printf ("rand[%d]= %u\n",
      i, rand ());
  }*/
  return 0;
}

Thx
Appreciate

Answer 1

well you can do something like this

#include <random>
#include <string>

std::string s("      "); //six spaces
std::random_device rd;
std::mt19937 engine(rd());
std::uniform_int_distribution<char> dist('0', 'z');

for(char& c : s)
{
    c=dist(eng);
}

however it will include some punctuation. you can modify it to ignore character outside of your accepted range.

http://en.cppreference.com/w/cpp/numeric/random

http://www.asciitable.com/

EDIT:
Merging mine and James answer together for a flexible solution could yeild something like this:

std::string const char_set(
    "abcdefghijklmnopqrstuvwxyz"
    "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
    "0123456789" );

std::string s("      "); //six spaces
std::random_device rd;
std::mt19937 engine(rd());
std::uniform_int_distribution<std::size_t> dist(0u, char_set.size() - 1);

for(char& c : s)
{
   c=char_set[dist(eng)];
}  

EDIT: I changed the end of the distribution to size() – 1, otherwise the terminating null will be included in the distribution.