Question

C++ Zybook Lab 16.5 LAB: Exception handling to detect input string vs. int

The given program reads a list of single-word first names and ages (ending with -1), and outputs that list with the age incremented. The program fails and throws an exception if the second input on a line is a string rather than an int. At FIXME in the code, add a try/catch statement to catch ios_base::failure, and output 0 for the age.

Ex: If the input is:

Lee 18
Lua 21
Mary Beth 19
Stu 33
-1

then the output is:

Lee 19
Lua 22
Mary 0
Stu 34

Here's the code:

#include <string>
#include <iostream>

using namespace std;

int main(int argc, char* argv[]) {
string inputName;
int age;
// Set exception mask for cin stream
cin.exceptions(ios::failbit);

cin >> inputName;
while(inputName != "-1") {
// FIXME: The following line will throw an ios_base::failure.
// Insert a try/catch statement to catch the exception.
// Clear cin's failbit to put cin in a useable state.
try{
//Reading age
cin >> age;
//Printing Name and age incremented by 1 if correct values are entered
cout << inputName << " " << (age + 1) << endl;
}
catch(ios_base::failure){
//Clear cin
cin.clear();
}
  
cin >> age;
cout << inputName << " " << (age + 1) << endl;

cin >> inputName;
}

return 0;
}

Answer 1

Please look at my code and in case of indentation issues check the screenshots.

---------------main.cpp----------------

#include <string>
#include <iostream>
using namespace std;

int main(int argc, char *argv[])
{
   string inputName;
   int age;
   // Set exception mask for cin stream
   cin.exceptions(ios::failbit);

   cin >> inputName;
   while (inputName != "-1")
   {
       // FIXME: The following line will throw an ios_base::failure.
       // Insert a try/catch statement to catch the exception.
       // Clear cin's failbit to put cin in a useable state.
       try
       {
          //Reading age
           cin >> age;
           //Printing Name and age incremented by 1 if correct values are entered
           cout << inputName << " " << (age + 1) << endl;
       }
       catch (ios_base::failure)
       {
          //Clear cin
          cout << inputName << " 0" << endl;       //on exception, print name and age as 0
           cin.clear();                           //clear the failbit
           cin.ignore(256,'\n');                   //ignore the current input until a new line '\n' is encountered
       }
      
       cin >> inputName;
   }
   return 0;
}

--------------Screenshots--------------------

------------------Output------------------

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