unordered_set::difference_type

The type of a signed distance between two elements.

typedef T3 difference_type;

Remarks

The signed integer type describes an object that can represent the difference between the addresses of any two elements in the controlled sequence. It is described here as a synonym for the implementation-defined type T3.

Example

// std_tr1__unordered_set__unordered_set_difference_type.cpp 
// compile with: /EHsc 
#include <unordered_set> 
#include <iostream> 
 
typedef std::unordered_set<char> Myset; 
int main() 
    { 
    Myset c1; 
 
    c1.insert('a'); 
    c1.insert('b'); 
    c1.insert('c'); 
 
// display contents " [c] [b] [a]" 
    for (Myset::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        std::cout << " [" << *it << "]"; 
    std::cout << std::endl; 
 
// compute positive difference 
    Myset::difference_type diff = 0; 
    for (Myset::const_iterator it = c1.begin(); 
        it != c1.end(); ++it) 
        ++diff; 
    std::cout << "end()-begin() == " << diff << std::endl; 
 
// compute negative difference 
    diff = 0; 
    for (Myset::const_iterator it = c1.end(); 
        it != c1.begin(); --it) 
        --diff; 
    std::cout << "begin()-end() == " << diff << std::endl; 
 
    return (0); 
    } 
 

 [c] [b] [a]
end()-begin() == 3
begin()-end() == -3

Requirements

Header: <unordered_set>

Namespace: std

See Also

Reference

<unordered_set>

unordered_set Class

unordered_set::size_type