Boost.LexicalCast which is defined in the Library “boost/lexical_cast.hpp” provides a cast operator, boost::lexical_cast, that can convert numbers from strings to numeric types like int or double and vice versa. boost::lexical_cast is an alternative to functions like std::stoi(), std::stod(), and std::to_string(), which were added to the standard library in C++11. Now let see the Implementation of this function in a program. Examples:
Conversion integer -> string string- > integer integer -> char float- > string
Associated exceptions : If a conversion fails, an exception of type bad_lexical_cast, which is derived from bad_cast, is thrown. It throws an exception because the float 52.50 and the string “GeeksforGeeks” cannot be converted to a number of type int.
// CPP program to illustrate // Boost.Lexical_Cast in C++ #include "boost/lexical_cast.hpp" #include <bits/stdc++.h> using namespace std;
using boost::lexical_cast;
using boost::bad_lexical_cast;
int main() {
// integer to string conversion
int s = 23;
string s1 = lexical_cast<string>(s);
cout << s1 << endl;
// integer to char conversion
array< char , 64> msg = lexical_cast<array< char , 64>>(45);
cout << msg[0] << msg[1] << endl;
// string to integer conversion in integer value
int num = lexical_cast< int >("1234");
cout << num << endl;
// bad conversion float to int
// using try and catch we display the error
try {
int num2 = lexical_cast< int >("52.20");
}
// To catch exception
catch (bad_lexical_cast &e) {
cout << "Exception caught : " << e.what() << endl;
}
// bad conversion string to integer character
// using try and catch we display the error
try {
int i = lexical_cast< int >("GeeksforGeeks");
}
// catching Exception
catch (bad_lexical_cast &e) {
cout << "Exception caught :" << e.what() << endl;
}
return 0;
} |
Output:-
23 45 1234 Exception caught : bad lexical cast: source type value could not be interpreted as target Exception caught :bad lexical cast: source type value could not be interpreted as target
Reference :- http://www.boost.org/