c++ - why its jumping out of program? -

i start learning c++.

when execute code it's jumping out of program without error. why?

#include "stdafx.h" #include <iostream>  using namespace std;  int _tmain(int argc, _tchar* argv[]) {    char s1[20],s2[10];   cout<<" enter number : ";   cin.get(s1,19);   cout<<" enter number : ";   cin.get(s2,9);    cout<<s1<<"/n"<<s2;    getch();  } 

the method get() reads upto '\n' character not extract it.

so if type: 122345<enter>
line:

cin.get(s1,19); 

will read 12345, '\n' (created hitting <enter>) left on input stream. next line read:

cin.get(s2,9); 

will read nothing sees '\n' , stops. not extract '\n' either. input stream still has '\n' there. line:

getch(); 

just reads '\n' character input stream. allows finish processing , exit program normally.

ok. happening. there more this. should not using get() read formatted input. use operator >> read formatted data correct type.

int main() {     int   x;     std::cin >> x; // reads number x                    // error if input stream not contain number. } 

because std::cin buffered stream data not sent program until push <enter> , stream flushed. useful read text (from user input) line @ time parse line independently. allows check last user input errors (on line line bases , reject if there errors).

int main() {     bool inputgood = false;         {         std::string  line;         std::getline(std::cin, line);   // read user line (throws away '\n')          std::stringstream data(line);         int  x;         data >> x;                   // reads integer line.                                      // if input not number data set                                      // error mode (note std::cin in example                                      // 1 above).         inputgood = data.good();     }     while(!inputgood);   // force user input again if there error.  } 

if want advanced can @ boost libs. provide nice code in general , c++ program should know contents of boost. can re-write above as:

int main() {     bool inputgood = false;         {         try         {            std::string  line;            std::getline(std::cin, line);   // read user line (throws away '\n')             int  x    = boost::lexical_cast<int>(line);            inputgood = true;               // if here lexical_cast worked.         }         catch(...) { /* throw away lexical_cast exception. forcing loop */ }     }     while(!inputgood);   // force user input again if there error.  }