函数原型:for_each(iterator beg, iterator end, _func);
其中: beg— 开始迭代器
end— 结束迭代器
_func— 函数或者函数对象
示例:
#include <algorithm> #include <vector> //普通函数 void print01(int val) { cout << val << " "; } //函数对象 class print02 { public: void operator()(int val) { cout << val << " "; } }; //for_each算法基本用法 void test01() { vector<int> v; for (int i = 0; i < 10; i++) { v.push_back(i); } //遍历算法 for_each(v.begin(), v.end(), print01); cout << endl; for_each(v.begin(), v.end(), print02()); cout << endl; } int main() { test01(); system("pause"); return 0; }
功能描述: 搬运容器到另一个容器中
函数原型: transform(iterator beg1, iterator end1, iterator beg2, _func);
//beg1 源容器开始迭代器
//end1 源容器结束迭代器
//beg2 目标容器开始迭代器
//_func 函数或者函数对象—对数据做逻辑运算
示例:
#include<vector> #include<algorithm> //常用遍历算法 搬运 transform class TransForm { public: int operator()(int val) { return val+100; } }; class MyPrint { public: void operator()(int val) { cout << val << " "; } }; void test01() { vector<int>v; for (int i = 0; i < 10; i++) { v.push_back(i); } vector<int>vTarget; //目标容器 vTarget.resize(v.size()); // 目标容器需要提前开辟空间 transform(v.begin(), v.end(), vTarget.begin(), TransForm()); for_each(vTarget.begin(), vTarget.end(), MyPrint()); } int main() { test01(); system("pause"); return 0; }
示例:
#include<iostream> #include<vector> using namespace std; int main() { int a[] = { 1,2,3,5,2,0 }; vector<int>counts(a,a+6); for (auto count : counts) cout<< count<< " "; cout << endl; return 0; }
void reverse_index(vector<vector<int>> vec) { int i,j; cout << "Use index : " << endl; for (i = 0; i < vec.size(); i++) { for(j = 0; j < vec[i].size(); j++) cout << vec[i][j] << " "; cout << endl; } }
void reverse_iterator(vector<vector<int>> vec) { vector<int>::iterator it; vector<vector<int>>::iterator iter; vector<int> vec_tmp; cout << "Use iterator : " << endl; for(iter = vec.begin(); iter != vec.end(); iter++) { vec_tmp = *iter; for(it = vec_tmp.begin(); it != vec_tmp.end(); it++) cout << *it << " "; cout << endl; } }