public member function
<string>
iterator begin();
const_iterator begin() const;
iterator begin() noexcept;
const_iterator begin() const noexcept;
Return iterator to beginning
Returns an iterator pointing to the first character of the string.
Return Value
An iterator to the beginning of the string.
If the basic_string object is const-qualified, the function returns a const_iterator. Otherwise, it returns an iterator.
Member types iterator and const_iterator are random access iterator types (pointing to a character and to a const character, respectively).
Example
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// string::begin/end
#include <iostream>
#include <string>
int main ()
{
std::string str ("Test string");
for ( std::string::iterator it=str.begin(); it!=str.end(); ++it)
std::cout << *it;
std::cout << '\n';
return 0;
}
| |
Output:
Iterator validity
Generally, no changes.
On some implementations, the non-const version may invalidate all iterators, pointers and references on the first access to string characters after the object has been constructed or modified.
Data races
The object is accessed, and in some implementations, the non-const version modifies it on the first access to string characters after the object has been constructed or modified.
The iterator returned can be used to access or modify characters.
Complexity
Unspecified, but generally constant.
Iterator validity
No changes.
Data races
The object is accessed (neither the const nor the non-const versions modify it).
The iterator returned can be used to access or modify characters. Concurrently accessing or modifying different characters is safe.
Exception safety
No-throw guarantee: this member function never throws exceptions.
The copy construction or assignment of the returned iterator is also guaranteed to never throw.