string::at
This member function behaves as
operator[] , except that
at also performs a range check, throwing an exception of type
out_of_range in case that
pos is not an actual position in the string
和[]运算符不同的地方是当它接受一个非法的参数的时候,会抛出异常
1 const char& at ( size_t pos ) const;
2 char& at ( size_t pos );
1 // string::at
2 #include <iostream>
3 #include <string>
4 using namespace std;
5
6 int main ()
7 {
8 string str ("Test string");
9 int i;
10 for (i=0; i < str.length(); i++)
11 {
12 cout << str.at(i);
13 }
14 return 0;
15 }