我的随机数生成器出现问题，数字超出范围

Question

I'm trying to make a Sudoku puzzle generator for a school project, and I have most of the coding and logic worked out for the program, it's just that the random number generator I'm using to assign values to the Sudoku grid are generating numbers far out of the appropriate range, and I can't quite figure out why it's not functioning appropriately. Here's the code for the number generator:

int Sudoku::RNG(int range, int start){
    int randNum;
    randNum = (rand()%range+start);
    return randNum;
}

I've also seeded with

srand(time(NULL)); 

at the very start of my main method.

And here's the code for the method which populates the Sudoku grid with numbers from the RNG() function:

void Sudoku::gridPopulate(int grid [9][9]){
    Solution s;
    int num;
    bool safe;
    for(int i=0;i<9;i++){
        for(int j=0;j<9;j++){
            do{
                safe = false;
                num= RNG(9,1);
                if(s.rowCheck(grid, i, num)&& s.colCheck(grid, j, num) && s.gridCheck(grid, i, j, num)){
                    grid[i][j] = num;
                    cout << "Number entered into grid" << endl;
                    safe = true;
                }
            }while(safe);
        }
    }

Main Method:

int main()
{
    //Program Start
    srand(time(NULL));
    int difficulty;
    int choice;
    int grid[9][9];

    cout << "Welcome to my Sudoku puzzle generator! \nTest your mental muscles and see if you can solve the puzzle!" << endl;

    //Puzzle Generator
    Sudoku game;
    game.gridPopulate(grid);
    cout << "board populated"<< endl;
    cout << "Successful board made" << endl;
    game.displayBoard(grid);
}

Example of erroneous Sudoku board below (formatting is off because of the huge numbers, just ignore the dashes and vertical lines):

1  5013192 4981028 9 |20064 8 5 |1 2 3 |
2  8 5 4 |1995768265 0 2114351727 |28 7670880 7670908 |
3  1 7274056 7 |3 0 7670880 |4 6 7670880 |
   -----------------4  6 7 2 |4199040 1 8 |7670912 -1196314433 4 |
5  1953657218 1 0 |5 4 32 |7 3 7274140 |
6  5 8 1953722109 |2 9 7670916 |7274116 4199040 4358512 |
   -----------------7  0 1953722297 1 |9 1953787893 3 |7274204 4 8 |
8  1953722109 1953722083 8 |4199040 4199040 0 |9 7274160 2 |
9  3 1953746112 1198757840 |6 7274216 4 |4358512 7274368 4358606 |
   -----------------

   1 2 3 4 5 6 7 8 9

The number's it's giving me are sometimes very large, sometimes not. It's kinda baffling me at the moment, any help or advice would be greatly appreciated!

EDIT/UPDATE #1:

I've revised my gridPopulate code, and I've added in a few cout statements for troubleshooting. The method will now stay on each individual array element until it is populated, the main issue I'm running into now is that the code will get stuck in the do/while statement where the RNG() is occurring. I'm using the counter to track how many RNG iterations it goes through before passing a safe value into the grid. The problem is that the RNG is going through way too many iterations before happening to generate a safe value, sometimes thousands of iterations before moving on. At some point it will just get stuck endlessly generating random numbers without being able to move on.'

   void Sudoku::gridPopulate(int grid [9][9]){
        Solution s;
        int num;

        do{
            for(int i=0;i<9;i++){
                for(int j=0;j<9;j++){
                    int counter = 0;
                    do{
                        srand(time(NULL));
                        num = RNG(9,1);
                        counter++;
                        cout << "RNG attempts: " << counter << endl;
                    }while(!(s.rowCheck(grid, i, num)&& s.colCheck(grid, j, num) && s.gridCheck(grid, i, j, num)));
                grid[i][j]=num;
                cout << grid[i][j] << endl;
                cout << "Row #: " << i << endl;
                cout << "Col #: " << j << endl;
                }//end j loop
                displayBoard(grid);
            }//end i loop
            displayBoard(grid);
        }while(!validityCheck(grid));

Here's my displayBoard method too, though I don't think it is correlated to the problem.

void Sudoku::displayBoard(int grid[9][9]){
    /**********************************************************/
    cout << "   ----------------------" << endl;
    for(int i=0; i<9;i++){
        if(i==0)
            cout << "1  | ";
        if(i==1)
            cout << "2  | ";
        if(i==2)
            cout << "3  | ";
        if(i==3)
            cout << "4  | ";
        if(i==4)
            cout << "5  | ";
        if(i==5)
            cout << "6  | ";
        if(i==6)
            cout << "7  | ";
        if(i==7)
            cout << "8  | ";
        if(i==8)
            cout << "9  | ";
        for(int j=0;j<9;j++){
            cout << grid[i][j] << " ";
            if(j==2)
            cout << "| ";
            if(j==5)
            cout << "| ";
            if(j==8)
            cout << "| ";
        }
        cout << endl;
        if(i==2)
            cout << "   ------------------------" << endl;
        if(i==5)
            cout << "   ------------------------" << endl;
        if(i==8)
            cout << "   ------------------------" << endl;
    }
    cout << "\n";
    cout << "     1 2 3   4 5 6   7 8 9 " << endl;

    /**********************************************************/
}

Answer 1

Nothing wrong with the RNG function, all we need is debugging skills
## Try this to see what is the immediate value of the grid[i][j] ##
`void Sudoku::void gridPopulate(int grid[9][9]) 
{
        Solution s;
        int num;
        bool safe;
        for (int i = 0; i < 9; i++) {
            for (int j = 0; j < 9; j++) {
                do {
                    safe = false;
                    num = RNG(9, 1);
                    if (s.rowCheck(grid, i, num) && s.colCheck(grid, j, num) && s.gridCheck(grid, i, j, num)) {
                        grid[i`enter code here`][j] = num;
                        //cout << "Number entered into grid" << endl;
                        safe = true;
                    }
                } while (safe);
                cout << grid[i][j] << " ";
            }
            cout << endl;
        }
    }`