adjacent_find()
binary_search()
binary_search()
count()
count_if()
find()
find_if()
adjacent_find()
在iterator对标识元素范围内，查找一对相邻重复元素，找到则返回指向这对元素的第一个元素的迭代器。否则返回past-the-end。
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| vector<int> vecInt;
vecInt.push_back(1);
vecInt.push_back(2);
vecInt.push_back(2);
vecInt.push_back(4);
vecInt.push_back(5);
vecInt.push_back(5);
vector<int>::iterator it = adjacent_find(vecInt.begin(), vecInt.end()); //*it == 2
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binary_search
在有序序列中查找value,找到则返回true。注意：在无序序列中，不可使用。
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| set<int> setInt;
setInt.insert(3);
setInt.insert(1);
setInt.insert(7);
setInt.insert(5);
setInt.insert(9);
bool bFind = binary_search(setInt.begin(),setInt.end(),5);
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count()
利用等于操作符，把标志范围内的元素与输入值比较，返回相等的个数。
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| vector<int> vecInt;
vecInt.push_back(1);
vecInt.push_back(2);
vecInt.push_back(2);
vecInt.push_back(4);
vecInt.push_back(2);
vecInt.push_back(5);
int iCount = count(vecInt.begin(),vecInt.end(),2); //iCount==3
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count_if()
假设vector<int> vecIntA，vecIntA包含1,3,5,7,9元素
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| //先定义比较函数
bool GreaterThree(int iNum)
{
if(iNum>=3)
{
return true;
}
else
{
return false;
}
}
int iCount = count_if(vecIntA.begin(), vecIntA.end(), GreaterThree);
//此时iCount == 4
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find()
find: 利用底层元素的等于操作符，对指定范围内的元素与输入值进行比较。当匹配时，结束搜索，返回该元素的迭代器。
equal_range: 返回一对iterator，第一个表示lower_bound,第二个表示upper_bound。
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| vector<int> vecInt;
vecInt.push_back(1);
vecInt.push_back(3);
vecInt.push_back(5);
vecInt.push_back(7);
vecInt.push_back(9);
vector<int>::iterator it = find(vecInt.begin(), vecInt.end(), 5); //*it == 5
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find_if()
find_if: 使用输入的函数代替等于操作符执行find。返回被找到的元素的迭代器。
假设vector<int> vecIntA，vecIntA包含1,3,5,3,9元素
vector<int>::it = find_if(vecInt.begin(),vecInt.end(),GreaterThree);
此时*it==3, *(it+1)==5, *(it+2)==3, *(it+3)==9
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| #define _CRT_SECURE_NO_WARNINGS
#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
void test_adjacent_find()
{
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
vector<int>::iterator it = adjacent_find(v.begin(), v.end());
cout << "*it: " << *it << endl;
cout << "distance: " << distance(v.begin(),it) << endl;
}
void test_binary_search() {
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
v.push_back(-1);
if (binary_search(v.begin(), v.end(), 5))
{
cout << "yes" << endl;
}
else
{
cout << "no" << endl;
}
}
void test_count() {
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
v.push_back(-1);
cout << "count: " << count(v.begin(), v.end(), 3) << endl;
}
bool Com(int x) {
if (x > 3) {
return true;
}
return false;
}
void test_countif() {
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
v.push_back(-1);
cout << "count_if: " << count_if(v.begin(), v.end(), Com) << endl;
}
void test_find() {
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
v.push_back(-1);
vector<int>::iterator it = find(v.begin(),v.end(),-1);
cout << "*it: " << *it << endl;
cout << "distance: " << distance(v.begin(),it) << endl;
}
class ComP {
public:
bool operator()(int x) {
if (x > 3)
{
return true;
}
return false;
}
private:
};
void test_findif() {
vector<int> v;
v.push_back(0);
v.push_back(1);
v.push_back(2);
v.push_back(3);
v.push_back(3);
v.push_back(5);
v.push_back(-1);
cout << "find_if: " << *(find_if(v.begin(), v.end(), ComP())) << endl;
}
int main(char *argv[], int argc)
{
test_adjacent_find();
test_binary_search();
test_count();
test_countif();
test_find();
test_findif();
return 0;
}
|
