非重复随机数 2D 向量 (C++）

>EDIT：我目前正在做一个项目。我几乎完成了，尽管我似乎无法弄清楚如何用非重复的随机数填充我的向量(矩阵(。我得到的是随机数，但其中一些是重复的。我尝试实现一种方法来检查推送到向量的数字是否已经存在，但这不起作用。

有没有简单的方法可以解决这个问题？

#include <iostream>
#include <iomanip>
#include <vector>
#include <cstdlib>
#include <ctime>
using namespace std;
/*
The purpose of this program is to create a matrix using 2D vectors, then decide
if it is a perfect matrix or not.
*/
void matrix(int );
int main()
{
    int input;
    char again = 'y';
    cout << "Welcome to my perfect matrix program. The function of the program is"
            "nto:"
            "n"
            "n   1. Allow the user to enter the size of the perfect matrix, such as"
            "n      N. N>=2."
            "n   2. Create a 2 D vector array of size N x N."
            "n   3. Populate the 2 D vector array with distinct random numbers."
            "n   4. Display the sum for each row, column, and diagonals then"
            "n      determine whether the numbers in N x N vector array are perfect"
            "n      matrix numbers.";
    cout << endl << endl;
    while(again == 'y' || again == 'Y')
    {
        cout << "nEnter the size of the matrix : ";
        cin >> input;
        while(input < 2)
        {
            cout << "nError *** Incorrect input - You entered a number < 2"
                    "nEnter a Positive integer Number >= 2: ";
            cin >> input;
        }
        matrix(input);
        cout << "nWould you like to find another perfect matrix?"
                "nEnter y || Y for yes or n || N for no: ";
        cin >> again;
        if(again == 'N' || again == 'n')
        {
            cout << "nThis perfect matrix algorithm is implemented by B"
                    "nFebruary 13th - 2017n";
        }
        while(again != 'Y' && again != 'y' && again != 'N' && again != 'n')
        {
            cout << "nError *** Invalid choice - Must enter y|Y or n|N" << endl;
            cout << "nWould you like to find another perfect matrix?"
                    "nEnter y || Y for yes or n || N for no: ";
            cin >> again;
        }
    }
    return 0;
}
void matrix(int value)
{
    int N = value;
    bool isPerf = true;
    int sum = 0,
        i,
        j;
    int diagSum1 = 0,
        diagSum2 = 0;
    vector<vector<int> >arr;
    srand(time(0));
    for(i = 0; i < N; i++)
    {
        vector<int> temp;
        bool check;
        int digit;
        for(j = 0; j < N; j++)
        {
            do
            {
                digit = rand()%8;
                check = true;
                for(int k = 0; k < j; k++)
                {
                    if(digit == temp.front())
                    {
                        check = false;
                        break;
                    }
                }
            }while(!check);
            temp.push_back(digit);
        }
        arr.push_back(temp);
    }
    cout << endl;
    cout << "The perfect matrix that is created for size " << value << ":";
    cout << endl << endl;
    for(i = 0; i < arr.size(); i++)
    {
        for(j = 0; j < arr[i].size(); j++)
        {
            cout << arr[i][j];
            cout << "   ";
        }
        cout << endl << endl;
    }
    for(i = 0; i < arr.size(); i++)
    {
        for(j = 0; j < arr[i].size(); j++)
        {
            sum += arr[i][j];
        }
    }
    int perf = sum/3;
    cout << "The perfect number is: " << perf << endl << endl;
    for(i = 0; i < arr.size(); i++)
    {
        int rowSum = 0;
        for(j = 0; j < arr[i].size(); j++)
        {
            rowSum += arr[i][j];
        }
        cout << "Sum of numbers in Row # " << i + 1 << " = " << rowSum;
        if(rowSum != perf)
        {
            isPerf = false;
        }
        cout << endl;
    }
    cout << endl;

    for(i = 0; i < arr.size(); i++)
    {
        int colSum = 0;
        for(j = 0; j < arr[i].size(); j++)
        {
            colSum += arr[j][i];
        }
        cout << "Sum of numbers in Column # " << i + 1 << " = " << colSum;
        if(colSum != perf)
        {
            isPerf = false;
        }
        cout << endl;
    }
    cout << endl;

for(i = 0; i < arr.size(); i++)
{
        diagSum1 += arr[i][i];
        diagSum2 += arr[i][arr.size() - i - 1];
}
cout << "Sum of numbers in first diagonal    =   " << setw(3) << diagSum1 << endl;
if(diagSum1 != perf)
    {
        isPerf = false;
    }
cout << "Sum of numbers in second diagonal   =   " <<  setw(3) << diagSum2 << endl;
if(diagSum2 != perf)
    {
        isPerf = false;
    }
cout << endl;
if(isPerf)
{
    cout << "The above is a perfect matrix" << endl;
}
else
    cout << "The above is not a perfect matrix" << endl;
cout << endl;

}