Returns a reference to the character at the specified location pos. The function automatically checks whether pos is the valid position of a character in the string (i.e., whether pos is less than the string length), throwing an out_of_range exception if it is not.
Syntax:
reference at (size_type pos); const_reference at (size_type pos) const; Parameters : pos - position of the character to return Return value : Reference to the requested character Exceptions : Throws std::out_of_range if pos >= size().
// CPP program to access a character through // std::basic_string::at #include <stdexcept> #include <iostream> int main()
{ // String with valid indices from 0 to 2
std::string str = "abc" ;
// Printing size of string
std::cout << "string size = " << str.size() << '\n' ;
// Accessing out of bounds index
try {
str.at(4) = 't' ;
}
// If error is generated, it is caught
catch (std::out_of_range const & error)
{
std::cout << error.what() << '\n' ;
}
} |
Output:
string size = 3 basic_string::at: __n (which is 4) >= this->size() (which is 3)