C ++数学游戏十六进制转换为小数

Question

I have completed the first two modes successfully of this math game which I am working on. I am struggling with the Hex to decimal portion though . The random isn't as random as I would like it to be. I want the Hex code to cout more random letters and in different spots: instead of just one letter in the same place. Also I would like to keep the amount of character output to a minimum of 7.

Could someone explain to me the flaw in my code, give me a working example, or some guidance in the right direction?

Please help me stackoverflow,

your my only hope!

Here is a picture of the game so far,

The following is the portion of the code of which I'm having an issue with. It's not fancy with classes or anything, just a simple function prototype as I'm still fairly new to c++ and programming.

void gamethree()
{

    float secs;
    secs = 33;
    clock_t delay = secs * CLOCKS_PER_SEC;              
    clock_t start = clock();
    int correct = 0;                                    

while (clock() - start < delay )
{
    srand(time(NULL));

    int hexdigits[15] = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15};
    char hexletters[7] = {'a', 'b', 'c', 'd', 'e', 'f'};
    //
    //enum letters{

    //  hexa = 10, 
    //  hexb = 11, 
    //  hexc = 12, 
    //  hexd = 13, 
    //  hexe = 14, 
    //  hexf = 15
    //};
    //hexa == hexletters[0];
    //hexb == hexletters[1];
    //hexc == hexletters[2];
    //hexd == hexletters[3];
    //hexe == hexletters[4];
    //hexf == hexletters[5];

    int randindex = rand() % 14;
    int randindexx = rand() % 6;
    cout << hexdigits[randindex];
    cout << hexletters[randindexx];


    int hexf[4] = {
        hexdigits[randindexx], 
        hexdigits[randindex], 
        hexletters[randindexx], 
        hexdigits[randindex],
    };


    random_shuffle(begin(hexf), end(hexf));

    for(int hi = 0; hi < 4; ++hi)
        cout << hexf[hi];
        char hexy = 0;
    cin >> hexy;

    //int hexy = 0;
    //cin >> hexy;



    ////int c = (a * b);
    //int d = 0;
    //char choice = 0;

    //cout <<"What does " << a << " * " << b << " equal?" << endl << endl << endl;
    //cout << "\n";

    //do
    //{
    //  cout << "Please enter a number: ";
    //  cin >> d;       
    //  if(d == c)
    //       ++correct;
    //}while(d != c);

    //cout << "\n\nCorrect! " << (a * b) << " is the answer!" << endl << endl;  
}
    cout << "Your score is: " << correct << "\n\n" <<endl;
cout << "Would you like to play again (Y) or (N)?\n\n\n";
}

void hextodec()
{
        float secs;
        secs = 1;
        clock_t delay = secs * CLOCKS_PER_SEC;              
        clock_t start = clock();
        while (clock() - start < delay )
            ;


        char choice = 'z';
        gamethree();
        while(choice != 'n')
        {

        cin >> choice;

        if (choice == 'y')
        {
            cout << "\n\n";
            game();
        }
        else
            choice = 'n';

    }


}

Answer 1

What I would do if this was my problem would be to have one one array full of all available characters then have a function to generate a string of max length from that, something like this.

std::string rand_string(const char* possible, int options, int max_length){
    std::string result; //we're using strings just so we don't have to pass a char*
    int length = rand()%max_length+1; //You may want to try to biase this towards bigger values or just set it at some value

    for (int i=0; i<length; ++i) {
        result[i]=possible[rand()%options]; //simple really
    }

    return result;
}

Basically just put all you characters in one array and loop through that.

Couple side notes. Why does your hexdigits array go up to 15. 15 is not a valid character in hex for the simple reason that it can't be distinguished from 1,5. Also what is this for. I'd hate to be helping you cheat on a assignment, though as this has not been tested and is probably obviously plagiarized were you to just use it whole sale I'm not too concerned.