18.4 Example Program: Exceptions

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NOTE: This program is in the file exceptn.cpp.

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This following example program demonstrates the use of exceptions:

#include <stdexcept>
#include <string>

static void f() { throw runtime_error("a runtime error"); }

int main ()
{
  string s;
  
  // First we'll try to incite then catch an exception 
  // from the Standard C++ Library string class.
  // We'll try to replace at a position that is non-existent.
  //
  // By wrapping the body of main in a try-catch block we can be
  // assured that we'll catch all exceptions in the exception
  // hierarchy. You can simply catch an exception as is done below,
  // or you can catch each of the exceptions in which you have an 
  // interest.
  try
  {
    s.replace(100,1,1,'c');
  }
  catch (const exception& e)
  {
    cout << "Got an exception: " << e.what() << endl;
  }

  // Now we'll throw our own exception using the function 
  // defined above.
  try
  {
    f();
  }
  catch (const exception& e)
  {
    cout << "Got an exception: " << e.what() << endl;
  }
 
 return 0;
}