"do while problem"

[SneakyPeterson]

Did you make sure to add this code?

bool set = false;
          while(!set)
          {
            aux2=int( rand()%20);
            aux3=int( rand()%20);
            if(math[aux2][aux3]==0)
            {
               math[aux2][aux3] = 1;
               set = true;
            }
           }

bool set = false;
          while(!set)
          {
            aux2=int( rand()%20);
            aux3=int( rand()%20);
            if(math[aux2][aux3]==0)
            {
               math[aux2][aux3] = 1;
               set = true;
            }
           }

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The while loop should keep running until you have set a value to 0. This added in conjunction with the initialization to 0 should fix your problem. Also, if you have the bool in the wrong place then the loop will
not work.