vector::begin (STL/CLR)

vector::begin (STL/CLR)

Designates the beginning of the controlled sequence.

    iterator begin();

 Remarks

The member function returns a random-access iterator that designates the first element of the controlled sequence, or just beyond the end of an empty sequence. You use it to obtain an iterator that designates the current beginning of the controlled sequence, but its status can change if the length of the controlled sequence changes.

 Example

// cliext_vector_begin.cpp 
// compile with: /clr 
#include  
 
int main() 
    { 
    cliext::vector c1; 
    c1.push_back(L'a'); 
    c1.push_back(L'b'); 
    c1.push_back(L'c'); 
 
// display initial contents " a b c" 
    for each (wchar_t elem in c1) 
        System::Console::Write(" {0}", elem); 
    System::Console::WriteLine(); 
 
// inspect first two items 
    cliext::vector::iterator it = c1.begin(); 
    System::Console::WriteLine("*begin() = {0}", *it); 
    System::Console::WriteLine("*++begin() = {0}", *++it); 
 
// alter first two items and reinspect 
    *--it = L'x'; 
    *++it = L'y'; 
    for each (wchar_t elem in c1) 
        System::Console::Write(" {0}", elem); 
    System::Console::WriteLine(); 
    return (0); 
    } 
运行结果

 a b c
*begin() = a
*++begin() = b
 x y c