visual c++ - C++ cin.clear() and cin.ignore(...) issue -

so, have several fields fill in numerals. , if try fill in input letters (ex. 'noway' or 'gg1337' - makes , error , asks valid number (without letters ex. '13' or '1500000').

but there 1 problem, if start fill input numbers , add letters (for ex. '12nowshithappens'), jumps next field of input, thinking valid number, showing error in next input field.

here function code:

int appled() {        cin >> appleds;     while(cin.fail())     {                cin.clear();         cin.ignore(numeric_limits<streamsize>::max(),'\n');         cout << "an arror occured!\nplease, enter valid number: ";         cin >> appleds;     }     return appleds; } 

if described wrong - here full code of test program :)

// exzerry presents   #include <iostream> #include <conio.h>  int apples; int fruit; int oranges; int x; int appleds; int orangeds;  using std::cout; using std::cin; using std::endl; using std::numeric_limits; using std::streamsize;  char newline = '\n';  bool ok;     bool ok2;    bool ok3;  int appled() //function receive 'apples' input {        cin >> appleds;     while(cin.fail())     {                cin.clear();         cin.ignore(numeric_limits<streamsize>::max(),'\n');         cout << "an arror occured!\nplease, enter valid number: ";         cin >> appleds;     }     return appleds; } int oranged() //function receive 'oranges' input {        cin >> orangeds;     while(cin.fail())     {         cin.clear();         cin.ignore(numeric_limits<streamsize>::max(),'\n');         cout << "an arror occured!\nplease, enter valid number: ";                 cin >> orangeds;     }     return orangeds; }  int main() {     ok = ok2 = ok3 = false; //some testing     while(!ok2) //actual program loop     {                x = 0; // dropping program restart.         //cout << "-----------------------" << endl;         //cout << "debug mode: " << x << endl;         //cout << "-----------------------" << endl;         cout << "=====================================================" << endl;         cout << "enter apples: ";         apples = appled();         cin.clear();         cin.ignore(numeric_limits<streamsize>::max(),'\n'); //now have apples         cout << "enter oranges: ";               apples = oranged();         cin.clear();         cin.ignore(numeric_limits<streamsize>::max(),'\n'); //and have oranges         cout << "\n=====================================================" << endl;         cout << "calculating..." << endl;         cout << "=====================================================" << endl;         fruit = apples + oranges;         cout << "in total have " << fruit << " fruit" << endl;         cout << "=====================================================" << endl;         cout << newline;         //option go out or continue loop         //if enter 1 - resets program, other char - exit         cout << "go out? (1 - 'no', others - 'yeap'):" << "  ";          cin >> x;         cout << newline;         // ok2 = true;         if (x == 1)          {             cout << "continue program..." << endl;             //cout << "-----------------------" << endl;             //cout << "debug mode: " << x << endl;             //cout << "-----------------------" << endl;             cin.clear();             cin.ignore(numeric_limits<streamsize>::max(),'\n');             ok = false;             ok3 = false;             continue;         }         if (x == 0)         {             cout << "shutting down app..." << x << endl;             //cout << "-----------------------" << endl;             //cout << "debug mode: " << x << endl;             //cout << "-----------------------" << endl;             break;         }         else          {             cout << "shutting down app..." << x << endl;             //cout << "-----------------------" << endl;             //cout << "debug mode: " << x << endl;             //cout << "-----------------------" << endl;             break;               }     }     cout << "press key exit :d" << endl;     getch();     return 0; } 

you can make own facet parses character sequence add invalid. this:

class num_get : public std::num_get<char> { public:     iter_type do_get( iter_type it, iter_type end, std::ios_base& str,                       std::ios_base::iostate& err, long& v) const     {         auto& ctype = std::use_facet<std::ctype<char>>(str.getloc());         = std::num_get<char>::do_get(it, end, str, err, v);          if (it != end && !(err & std::ios_base::failbit)                       && ctype.is(ctype.alpha, *it))             err |= std::ios_base::failbit;          return it;     } }; 

now can install stream:

std::locale orig(std::cin.getloc()); std::cin.imbue(std::locale(orig, new num_get));  while (!(std::cin >> appleds)) {     // input not entirely numeric }  // input entirely numeric