set_difference()

set_difference()演算法計算兩個集合[start1, end1)和[start2, end2)的差集, 並將差集存放到result.

兩個集合以序列的形式給出, 且必須先按升序排好位置.

set_difference()是一個指向result序列末尾的迭代器.

如果嚴格弱排序的比較函數對象cmp未指定, set_difference()將使用<操作符比較元素.

範例

// set_difference example#include <iostream>#include <algorithm>#include <vector>using namespace std; int main () {  int first[] = {5,10,15,20,25};  int second[] = {50,40,30,20,10};  vector<int> v(10);                           // 0  0  0  0  0  0  0  0  0  0  vector<int>::iterator it;   sort (first,first+5);     //  5 10 15 20 25  sort (second,second+5);   // 10 20 30 40 50   it=set_difference (first, first+5, second, second+5, v.begin());                                               // 5 15 25  0  0  0  0  0  0  0   cout << "difference has " << int(it - v.begin()) << " elements.\n";   return 0;}
輸出: difference has 3 elements