C++ random number generator only generates 0 - C++ 11 - c++

Question

I am trying to generate a random number between 0 and 2 (inclusive) for a C++ program:
#include <iostream>
#include <string>
#include <cstdlib>
#include <random>
using namespace std;
int generateRowMovement(){
//http://www.cplusplus.com/reference/random/uniform_int_distribution/
default_random_engine generator;
uniform_int_distribution<int> distribution(0,2);
int row = distribution(generator);
return row;
}
int main(){
int row = generateRowMovement();
cout << row << endl;
int row2 = generateRowMovement();
cout << row2 << endl;
int row3 = generateRowMovement();
cout << row3 << endl;
return 0;
}
All 3 results are:
0
0
0
I have been testing this for 30 minute and it is always zero. I have tried following this link and this SO post (which posts link back to), but none of their solution is fix this problem. How can I generate 0, 1, and 2?

Answer 1

There are two issues with the code you posted that keeps it from working how you intend it to. The first is that generator is never given a seed, or as is commonly shown online, a random_device, ie
random_device rd;
default_random_engine generator(rd());
The second is that every time you call the function, you're creating a new random engine, and a new distribution. It would be better to create a random device, give it to to the engine only once, and then let your function return the values based on those.
#include <iostream>
#include <string>
#include <cstdlib>
#include <random>
using namespace std;
random_device rd;
default_random_engine generator(rd());
uniform_int_distribution<int> distribution(0,2);
int generateRowMovement(){
return distribution(generator);
}
int main(){
int row = generateRowMovement();
cout << row << endl;
int row2 = generateRowMovement();
cout << row2 << endl;
int row3 = generateRowMovement();
cout << row3 << endl;
return 0;
}