Implement operator-( ) and operator-=( ) for objects of type string: - C++ STL

C++ examples for STL:string

  1. HOME
  2. C++
  3. STL
  4. string

Description

Implement operator-( ) and operator-=( ) for objects of type string:

Demo Code

#include <iostream>
#include <string>
using namespace std;
string operator-(const string &left, const string &right);
string operator-=(string &left, const string &right);
int main()/* w ww . ja va 2s.  co  m*/
{
   string str("This is a test.");
   string res_str;
   cout << "Contents of str: " << str << "\n\n";
   // Subtract "is" from str and put the result in res_str.
   res_str =  str - "is";
   cout << "Result of str - \"is\": " << res_str << "\n\n";
   res_str -= "is";
   cout << "Result of res_str -= \"is\": " << res_str << "\n\n";
   cout << "Here is str again: " << str
   << "\nNotice that str is unchanged by the preceding "
   << "operations." << "\n\n";
   cout << "Here are some more examples:\n\n";
   // Attempt to subtract "xyz". This causes no change.
   res_str =  str - "xyz";
   cout << "Result of str - \"xyz\": " << res_str << "\n\n";
   // Remove the last three characters from str.
   res_str =  str - "st.";
   cout << "Result of str - \"st.\": " << res_str << "\n\n";
   // Remove a null string, which results in no change.
   res_str =  str - "";
   cout << "Result of str - \"\": " << res_str << "\n\n";
   return 0;
}
string operator-(const string &left, const string &right) {
   string::size_type i;
   string result(left);
   i = result.find(right);
   if(i != string::npos)
      result.erase(i, right.size());
   return result;
}
string operator-=(string &left, const string &right) {
   string::size_type i;
   i = left.find(right);
   if(i != string::npos)
      left.erase(i, right.size());
   return left;
}

Result


Related Tutorials