STL学习笔记（13）谓词

class GreaterThenFive
{
public:
    bool operator()(int num) { return num > 5; }
}; //一元谓词

void test01()
{
    vector<int> v;
    for (int i = 0; i < 10; i++)
    {
        v.push_back(i);
    }
    vector<int>::iterator it = find_if(v.begin(), v.end(), GreaterThenFive());
    if (it == v.end())
    {
        cout << "没有找到" << endl;
    }
    else
    {
        cout << "找到了: " << *it << endl;
    }
} //二元谓词
class MyCompare
{
public:
    bool operator()(int num1, int num2) { return num1 > num2; }
};
void test02()
{
    vector<int> v;
    v.push_back(10);
    v.push_back(40);
    v.push_back(20);
    v.push_back(90);
    v.push_back(60); //默认从小到大
    sort(v.begin(), v.end());
    for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
    {
        cout << *it << " ";
    }
    cout << endl;
    cout << "----------------------------" << endl; //使用函数对象改变算法策略，排序从大到小
    sort(v.begin(), v.end(), MyCompare());
    for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
    {
        cout << *it << " ";
    }
    cout << endl;
}