, имеющий проблему в случае вычитания (делая num3 всегда больше, чем num4 в случайном генераторе). кто знает, как

Question

#include<iostream> 
#include<iomanip> 
#include<cstdlib> 
#include"formatNumber.h" 
using namespace std; 

int main() 
{ 
    int choice; 
    int num1, num2, num3, num4, num5, num6; 
    int problem; 

    unsigned seed = time(0); 
    srand(seed); 

    cout << "This program will help you learn addition, subtraction,\n"; 
    cout << "multiplication, and division. Press any key to continue." << endl; 
    cin.get(); 

    do 
    { 
     cout << "Choose which math you would like to work on." << endl;  
     cout << "--------------------------------------------" << endl; 
     cout << "1. Addition\n"; 
     cout << "2. Subtraction\n"; 
     cout << "3. Multiplication\n"; 
     cout << "4. Quit program\n"; 
     cout << endl; 

     cout << "Choose 1,2,3,or 4: "; 
     cin >> choice; 


     switch(choice) 
     { 
     case 1: problem = 0; 
        num1 = rand() % 11; 
        num2 = rand() % 11; 

        while (problem != 999) 
        { 
         cout << "How much is " << num1 << " plus " << num2 << " (999 to exit)? "; 
         cin >> problem; 

         if (problem == 999) 
         break; 

         if (problem == (num1 + num2)) 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "Very good!\n"; 
            break; 
          case 1: cout << "Nice work!\n"; 
            break; 
          case 2: cout << "Excellent!\n"; 
            break; 
          case 3: cout << "Keep up the good work!\n"; 
            break; 
         } 

         num1 = rand() % 11; 
         num2 = rand() % 11; 
         } 
         else 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "No. Please try again\n"; 
            break; 
          case 1: cout << "Sorry. That's not it\n"; 
            break; 
          case 2: cout << "No. Don't give up\n"; 
            break; 
          case 3: cout << "Not yet. Keep trying\n"; 
            break; 
         cout << "How much is " << num1 << " plus " << num2 << "(999 to exit)? "; 
         cin >> problem; 
         } 

         } 
        } 
        break;      
     case 2: problem = 0; 
        num3 = rand() % 11; 
        num4 = rand() % 11; 

        while (problem != 999) 
        { 

         cout << "How much is " << num3 << " minus " << num4 << " (999 to exit)? "; 
         cin >> problem; 

         if (problem == 999) 
         break; 

         if (problem == (num3 - num4)) 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "Very good!\n"; 
            break; 
          case 1: cout << "Nice work!\n"; 
            break; 
          case 2: cout << "Excellent!\n"; 
            break; 
          case 3: cout << "Keep up the good work!\n"; 
            break; 
         } 

         num3 = rand() % 11; 
         num4 = rand() % 11; 
         } 
         else 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "No. Please try again\n"; 
            break; 
          case 1: cout << "Sorry. That's not it\n"; 
            break; 
          case 2: cout << "No. Don't give up\n"; 
            break; 
          case 3: cout << "Not yet. Keep trying\n"; 
            break; 
         cout << "How much is " << num1 << " plus " << num2 << "(999 to exit)? "; 
         cin >> problem; 
         }  
         } 
        } 
        break; 
     case 3: problem = 0; 
        num5 = rand() % 11; 
        num6 = rand() % 11; 

        while (problem != 999) 
        { 
         cout << "How much is " << num5 << " times " << num6 << " (999 to exit)? "; 
         cin >> problem; 

         if (problem == 999) 
         break; 

         if (problem == (num5 * num6)) 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "Very good!\n"; 
            break; 
          case 1: cout << "Nice work!\n"; 
            break; 
          case 2: cout << "Excellent!\n"; 
            break; 
          case 3: cout << "Keep up the good work!\n"; 
            break; 
         } 

         num5 = rand() % 11; 
         num6 = rand() % 11; 
         } 
         else 
         { 
         switch(rand() % 4) 
         { 
          case 0: cout << "No. Please try again\n"; 
            break; 
          case 1: cout << "Sorry. That's not it\n"; 
            break; 
          case 2: cout << "No. Don't give up\n"; 
            break; 
          case 3: cout << "Not yet. Keep trying\n"; 
            break; 
         cout << "How much is " << num1 << " plus " << num2 << "(999 to exit)? "; 
         cin >> problem; 
         } 

         } 
        } 
        break;     
     case 4: cout << "Thank you and have a good day!\n"; 
       break; 
     default : cout << "Invalid response! please choose (1,2,3,4,or 5)." << endl; 
        cin >> choice; 
    } 
    }while (choice != 4); 
     cin.get(); 

     return 0; 
} 

Эта программа позволяет пользователю решить, какую математику они хотят делать. остальное - список случайных чисел, сгенерированных для математических задач. Кто-нибудь знает, как всегда делать num3 больше или равно num4 в случае вычитания?

Answer 1

В качестве альтернативы вы можете просто добавить предложение if, чтобы проверить большее количество, и если num4 больше, чем num3, поменяйте их.

Или вы всегда можете суммировать num3 и num4 и использовать сумму как наибольшее число, I.e. num3, и используйте num4 как есть.

(Это несколько эквивалентно добавлению min/floor (которая равна num4) до num3 См:.. http://www.cplusplus.com/reference/cstdlib/rand/ для того, как генерировать случайное число в пределах диапазона)

Тем не менее, затем будет потенциальные проблемы переполнения. Итак, нет, первый способ еще лучше.