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  1. #include <iostream>
  2. #include <fstream>
  3. //#include <conio.h>
  4. #include <cstdlib>
  5. #include <string>
  6. #include <sstream>
  7. using namespace std;
  8.  
  9. int main()
  10. {
  11.     char user_info= ' ';
  12.     string string_convert;
  13.     int num1;
  14.     bool bfail=true;
  15.  
  16.  
  17.     do
  18.     {
  19.         bfail=true;
  20.         cout << "Enter num1: ";
  21.         while(user_info != '\n')
  22.         {
  23.             cin.get(user_info);
  24.             if(isdigit(user_info))
  25.                 string_convert+=user_info;
  26.             else if(user_info=='\n')
  27.             {
  28.              //   user_info=='\n';
  29.                 if(bfail==false)
  30.                     string_convert="";
  31.             }
  32.             else
  33.                 bfail=false;
  34.         }
  35.         user_info=' ';
  36.     }while(bfail!=true);
  37.     cerr << "before convert: " << string_convert << endl;
  38.     cout << "after convert: " << atoi(string_convert.c_str()) << endl;
  39.  
  40.  
  41.     return 0;
  42. }
Success #stdin #stdout #stderr 0s 3476KB
comments (?)
stdin 
123
stdout 
Enter num1: after convert: 123
stderr 
before convert: 123
https://ideone.com/9DWl0E
language:
C++14 (clang 8.0)
created:
7 years ago
visibility:
secret

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