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  1. #include <iostream>
  2. #include <sstream>
  3. #include <string>
  4. #include <cctype>
  5. using namespace std;
  6.  
  7. int main(){
  8. 	string str; //Store a number
  9.     int i=0; //Spit out the number
  10.  
  11.     cout << "Enter a number: ";
  12.  
  13.     while(getline(cin, str)){
  14. 	stringstream ss(str);
  15.         if (str.size()==0)
  16.             cout <<"\nPlease enter a valid number: ";
  17.         if (isdigit(str[0])==false)
  18.             cout <<"\nPlease enter a valid number: ";
  19.         else if (ss >> i && ss.eof())
  20.             break;
  21. 	else
  22.             cout <<"\nPlease enter a valid number: ";
  23.     }
  24.     if (cin) {
  25.     	cout << "\nThe value stored in string str was: " << i;
  26.     	cin.get();
  27.     }
  28.  	return 0;
  29. }
Success #stdin #stdout 0.02s 2688KB
comments (?)
stdin 
Standard input is empty
stdout 
Enter a number:
https://ideone.com/7wJ5G
language:
C++ (gcc 8.3)
created:
11 years ago
visibility:
public

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