c++ - I Can't Figure Out Why This Loop Is Malfunctioning -


so can't figure out what's wrong code. when process purchase, after enter amount of yogurt , told go enjoy it, after error message made if people don't input p or s, right afterwards goes normal when first enter program, tell me why is? thank you!

#include <iostream> #include <string> #include <sstream> using namespace std;  int main() {    string usercommand;    int creditcount = 0;    int userinput;     while (creditcount >= 0)    {        cout << "--------menu--------\n" << "p (process purchase)\n" << "s (shutdown system)\n"            << "--------menu--------\n" << "your choice: ";        getline(cin, usercommand);        if (usercommand[0] == 'p' || usercommand[0] == 'p')       {          if (creditcount >= 10)          {             cout << "you qualify free yogurt, use ten of credits (yes or no)?";              getline(cin, usercommand);              if (usercommand[0] == 'y' || usercommand[0] == 'y')             {                creditcount = creditcount - 10;                 cout << "you used 10 credits , have " << creditcount << " left.\n"                     << "enjoy free yogurt!";             }              else if (usercommand[0] == 'n' || usercommand[0] == 'n')             {                cout << "how many yogurts buy? ";                cin >> userinput;                 if (userinput > 0)                {                   creditcount = creditcount + userinput;                   cout << "you earned " << userinput << " stamps.  have " << creditcount                      << " credits!  enjoy yogurt!";                }                 else                {                   cout << "invalid input, please try processing purchase again , enter positive "                        << "integer.";                }             }              else             {                cout << "*error, please try processing purchase again , enter either yes or no*\n\n";             }          }           else if (creditcount < 10)          {             cout << "how many yogurts buy? ";             cin >> userinput;              if (userinput > 0)             {                creditcount = creditcount + userinput;                cout << "you earned " << userinput << " stamps.  have " << creditcount                     << " credits!  enjoy yogurt!\n\n";             }              else             {                cout << "invalid input, please try processing purchase again , enter positive "                     << "integer.";             }          }       }        else if (usercommand[0] == 's' || usercommand[0] == 's')       {          cout << "*shutting down system*\n";           return 0;       }        else       {          cout << "*error, please enter either p (for process purchase) or s (for shutdown system)*\n\n";       }     } }

@acid1789 has pointed out correctly error due empty line after getline. code can make out using infinite loop here

while(creditcount >= 0){...}

since creditcount never going less 0 instead of can use 

while (true){...}

its better programming practice.

and correct program can use 

cin >> usercommand;

instead of 

getline(cin, usercommand);

hope helps.

edit:- sorry python habits..


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