【C/C++学院】0830-兰不达表达式/STL算法-操作数据

兰不达表达式

#include<iostream>#include<vector>#include<algorithm>//算法  lambda表达式，不仅仅适用与array ,也适用于vectorvoid main1(){std::vector<int> myvector;myvector.push_back(11);myvector.push_back(22);myvector.push_back(33);myvector.push_back(3);myvector.push_back(4);myvector.push_back(5);int res=0;//结果//&res直接操作一个变量，res等价于返回值，x代表参数，每次充当迭代器指向的元素，大括号就是代码std::for_each(myvector.begin(), myvector.end(), [&res](int x){res += x; });std::cout << res;std::cin.get();}void main(){std::vector<int> myvector(5);//分配5个空间,默认初始化为0myvector.push_back(1);//增myvector.push_back(11);myvector.push_back(111);myvector.push_back(1111);myvector.push_back(2);myvector.pop_back();//弹出一个元素，删除最后一个myvector.insert(myvector.begin() +1, 999);//插入，myvector.erase(myvector.begin()+5);//根据迭代器的位置//myvector.clear();//删除所有元素for (int i = 0; i < myvector.size(); i++){if (1){//查询，修改}std::cout << myvector.at(i) << std::endl;}system("pause");}void main123123(){//可以实现动态无规则数组管理std::vector<int> myvetor1;myvetor1.push_back(12);myvetor1.push_back(13);myvetor1.push_back(14);std::vector<int> myvetor2;myvetor2.push_back(22);std::vector<int> myvetor3;myvetor3.push_back(32);myvetor3.push_back(37);std::vector<std::vector<int>> allvecor;allvecor.push_back(myvetor1);allvecor.push_back(myvetor2);allvecor.push_back(myvetor3);for (int i = 0; i < allvecor.size(); i++){for (int j = 0; j < allvecor[i].size(); j++){std::cout <<"  "<< allvecor[i][j];}std::cout << "\n";}std::cin.get();}

STL算法-操作数据

Vector

#include <iostream>#include <vector>#include <algorithm>#include <list>#include <set>#include <string>using namespace std;void main1(){vector<int> myv;myv.push_back(1);myv.push_back(2);myv.push_back(3);myv.push_back(11);myv.push_back(22);myv.push_back(33);for_each(myv.begin(), myv.end(), [](int v){ cout << v << endl; });auto  i = find(myv.begin(), myv.end(), 23);if (i==myv.end()){std::cout << "23玩失踪";} else{std::cout <<*i;}cin.get();}void main2(){vector<int> myv;myv.push_back(1);myv.push_back(2);myv.push_back(3);myv.push_back(11);myv.push_back(22);myv.push_back(33);for_each(myv.begin(), myv.end(), [](int v){ cout << v << endl; });//auto  i = find_if(myv.begin(), myv.end(), [](int v)->bool{ return (v > 4); });auto  i = find_if_not(myv.begin(), myv.end(), [](int v)->bool{ return (v > 4); });if (i == myv.end()){std::cout << "玩失踪";}else{std::cout << *i;}cin.get();}

List

template <class T>class show{public:void  operator ()(T &t){cout << t << "  ";}};void main3(){list <int >  list1;vector <int > v1;list1.push_back(121);list1.push_back(12);list1.push_back(122);list1.push_back(23);v1.push_back(121);v1.push_back(12);v1.push_back(122);v1.push_back(23);//sort(list1.begin(), list1.end());//排序//sort(v1.begin(), v1.end());//排序,简单的排序//算法依赖于数据结构（链式，线性），不同的数据结构，算法不一样    fill(v1.begin() + 3, v1.end(), 3);//填充，指定位置数据进行初始化for_each(list1.begin(), list1.end(), show<int>());cout << "\n";for_each(v1.begin(), v1.end(), show<int>());cin.get();}

Multiset 

void main4(){multiset<int > myset;myset.insert(3);myset.insert(1);myset.insert(2);myset.insert(1);myset.insert(2);myset.insert(1);myset.insert(2);myset.insert(1);int i = 0;for (auto ib = myset.begin(), ie = myset.end(); ib != ie;ib++,i++){}cout << i << endl;int num = count(myset.begin(), myset.end(), 1);//统计1有多少个节点cout << num<< endl;cin.get();}void  main5(){multiset<int > myset;myset.insert(3);myset.insert(1);myset.insert(2);myset.insert(1);myset.insert(0);myset.insert(1);myset.insert(2);myset.insert(1);for_each(myset.begin(),myset.end(), show< const int>());    auto  it=adjacent_find(myset.begin(), myset.end());cout << "\n" << *it << endl;it++;cout << "\n" << *it << endl;it++;cout << "\n" << *it << endl;it++;cout << "\n" << *it << endl;it = adjacent_find(it, myset.end());//查找相同的数据，可以自己确定位置cout << "\n" << *it << endl;it++;cout << "\n" << *it << endl;cin.get();}

打乱数据，扑克牌洗牌

template <class T>class show{public:void  operator ()(T &t){cout << t << "  ";}};//打乱数据void  main(){vector<int> v1;for (int i = 0; i < 10;i++){v1.push_back(i);}for_each(v1.begin(), v1.end(), show<int>());cout << "\n";random_shuffle(v1.begin(), v1.end());for_each(v1.begin(), v1.end(), show<int>());cout << "\n";random_shuffle(v1.begin(), v1.end());for_each(v1.begin(), v1.end(), show<int>());cout << "\n";random_shuffle(v1.begin(), v1.end());for_each(v1.begin(), v1.end(), show<int>());cin.get();}

旋转数据

bool isok(int num){return (num == 8);}//旋转数据void  main7(){vector<int> v1;for (int i =10; i>0; i--){v1.push_back(i);}for_each(v1.begin(), v1.end(), show<int>());//partition(v1.begin(), v1.end(), isok);//服务于快速排序法的分区//旋转， 头，尾，中间rotate(v1.begin(), v1.begin()+8, v1.end());//v1.begin(), v1.begin()+8之间的数据移动到后面cout << "\n";for_each(v1.begin(), v1.end(), show<int>());/*rotate(v1.begin(), v1.begin()+1, v1.end());cout << "\n";for_each(v1.begin(), v1.end(), show<int>());rotate(v1.begin(), v1.begin() + 1, v1.end());cout << "\n";for_each(v1.begin(), v1.end(), show<int>());rotate(v1.begin(), v1.begin() + 1, v1.end());cout << "\n";for_each(v1.begin(), v1.end(), show<int>());*/cin.get();}

排序并显示步骤

void  main8(){int a[4] = { 2, 1, 3 ,10};do {cout << a[0] << " " << a[1] << " " << a[2] <<a[3]<< "\n";} while (prev_permutation(a,a+4));//排序并显示步骤cin.get();}

局部排序

void  main10(){vector<char>one;one.push_back('B');one.push_back('A');one.push_back('C');one.push_back('Y');one.push_back('Z');one.push_back('X');for_each(one.begin(), one.end(), show<char>());cout << "\n";for_each(one.begin(), one.end(), show<char>());cin.get();}

取出分数最低的2个学生

#include <iostream>#include <vector>#include <algorithm>#include <list>#include <set>#include <string>using namespace std;class student{public: string name;int score;public:student(string str, int num) :name(str), score(num){}bool operator <(const student &s1)const{return this->score < s1.score;}};//去分数最差的2个人void  main(){vector<student> ss;{student s1("银城A", 106);ss.push_back(s1);}{student s1("银城B", 101);ss.push_back(s1);}{student s1("银城C", 103);ss.push_back(s1);}{student s1("银城D", 105);ss.push_back(s1);}partial_sort(ss.begin(), ss.begin() + 2,ss.end());//部分排序for (int i = 0; i < 4;i++){std::cout << ss[i].name << ss[i].score << "\n";}cin.get();}