1，容器函数的使用、lambad表达式的使用
2，源码
#include <iostream>
#include <algorithm>
#include <iterator>
#include <numeric>
#include <vector>
#include <list>
#include <string>
/*
算法：算法不会执行容器操作，因此他们自身不能改变容器大小
1，读容器一些函数
find：可以操作任何类型的容器和数组,如果找到值返回对应元素的迭代器
accumulate:求和算法
equal:查看两个序列是否有相等的值，相等返回true，不相等返回false
2，写容器一些函数
fill: 可以对容器进行写操作
fill_n: 对容器进行n个元素的写操作
3，back_inserter：插入迭代器
4，copy：拷贝函数，拷贝的目的序列至少要和输入序列一样多的元素
replace：替换函数
5，重新排序算法
sort： 排序
unique：消除相同元素，仅能比较相邻元素
6，相排序算法，添加函数
相算法添加的参数叫谓词
*/
using namespace std;
bool is_shorted(const string &s1, const string &s2)
{
return s1.size() < s2.size();
}
int main(void)
{
/*Find----------------------------------------------------------------------------------------------*/
//如果找到返回给定值元素的迭代器
vector<int> vector_num = {0,1,2,3,4,5,6,7,8,9,10};
auto vector_result = find(vector_num.begin(), vector_num.end(), 8);
cout << (vector_result == vector_num.end() ? "Data NO Find" : "Data Find") << endl;
list<string> string_buf = {"xiaohua", "xiaotao", "xiaogou", "xiaojun"};
string str= "xiaotao";
auto list_rsult = find(string_buf.begin(), string_buf.end(), str);
cout << (list_rsult == string_buf.end() ? "Data NO Find" : "Data Find") << endl;
int arry[] = {0,1,2,3,4,5,6,7,8,9,10};
int *arry_result = find(begin(arry), end(arry), 8);
cout << *arry_result <<endl;
/*accumulate--------------------------------------------------------------------------------------*/
//前两个参数初始化求和范围，最后一个参数初始化sum值为0
int sum = accumulate(vector_num.begin(), vector_num.end(), 0);
cout << "sum = " << sum <<endl;
//容器序列中的元素必须和第三个参数元素类型相同，或转换成第三个参数类型
//如果第三个元素不进行类型转换会出现一个<const char *>编译错误; ""为const char *类型
auto str_begin = string_buf.begin();
while (str_begin != string_buf.end())
{
*str_begin += "; ";
str_begin++;
}
string str_sum = accumulate(string_buf.begin(), string_buf.end(), string(""));
cout << str_sum << endl;
/*equal-----------------------------------------------------------------------------------------*/
list<string> equal_str1 = {"tian", "di", "ren", "he"};
list<string> equal_str2 = {"tian", "di", "ren", "he"};
bool result_equal = equal(equal_str1.cbegin(), equal_str1.cend(), equal_str2.cbegin());
cout << (result_equal ? "Equal" : "No Equal") << endl;
/*fill-----------------------------------------------------------------------------------------*/
//fill不进行容器操作，因此不会改变容器大小;fill_n算法不会检查写操作，所以在在指定操作长度时候一定要注意
fill(vector_num.begin(), vector_num.end(), 0);
cout << accumulate(vector_num.begin(), vector_num.end(), 0) << endl;
fill(vector_num.begin(), vector_num.begin()+vector_num.size()/2, 10);
cout << accumulate(vector_num.begin(), vector_num.end(), 0) << endl;
//下面使用方式比较危险,操作n个元素
fill_n(vector_num.begin(), 10, 10);
cout << accumulate(vector_num.begin(), vector_num.end(), 0) << endl;
/*back_inserter插入迭代器-----------------------------------------------------------------------*/
vector<int> back_inserter_num;
//创建一个插入迭代器，并添加10个元素
fill_n(back_inserter(back_inserter_num), 10, 0);
/*copy拷贝-------------------------------------------------------------------------------------*/
int a1[] = {0,1,2,3,4,5,6,7,8,9,10};
int a2[sizeof(a1)/sizeof(*a1)];
//a2和a1有相同的元素
copy(begin(a1), end(a1), a2);
//用80替换8
replace(begin(a1), end(a1), 8, 80);
/*sort或unique排序---------------------------------------------------------------------------*/
vector<string> string_words = {"My", "name", "is", "bandaostart", "My", "age", "is", "28"};
//sort排序
sort(string_words.begin(), string_words.end());
auto string_words_beg = string_words.begin();
while (string_words_beg != string_words.end())
{
cout << *string_words_beg++ << " ";
}
cout << endl;
//unique去掉重复，因为算法函数不能执行容器操作，需要使用容器操作函数来执行真正的删除
//返回重复元素迭代器地址,unique仅能比较相邻两个元素是否相同
auto unique_beg = unique(string_words.begin(), string_words.end());
string_words_beg = string_words.begin();
while (string_words_beg != string_words.end())
{
cout << *string_words_beg++ << " ";
}
cout << endl;
string_words.erase(unique_beg, string_words.end());
string_words_beg = string_words.begin();
while (string_words_beg != string_words.end())
{
cout << *string_words_beg++ << " ";
}
cout << endl;
/*重载算法函数------------------------------------------------------------------------------*/
//is_shorted为重载过的函数
sort(string_words.begin(), string_words.end(), is_shorted);
for(const auto &s : string_words)
{
cout << s << " ";
}
cout << endl;
return 0;
}
#include <iostream>
#include <algorithm>
#include <iterator>
#include <numeric>
#include <vector>
#include <string>
#include <functional>
/*
1，调用lambda表达式
[](const string &s1, const string &s2){ return s1.size()>s2.size();} //默认返回类型，不能包含return意外的语句
[](const string &s1, const string &s2) ->int { return s1.size()>s2.size();} //指定返回类型，可以包含return以外的语句
2，lambda参数传递
3，参数绑定
auto newcallable = bind(callable, arg_list);
*/
using namespace std;
using namespace std::placeholders;
bool check_sized(const string &s1, size_t sz)
{
return s1.size() > sz;
}
void sort_num(int num1, int num2, int num3, int num4, int num5)
{
cout << num1 << " ";
cout << num2 << " ";
cout << num3 << " ";
cout << num4 << " ";
cout << num5 << " ";
cout << endl;
}
int main(void)
{
vector<string> string_words = {"My", "name", "is", "bandaostart", "My", "age", "is", "28"};
/*lambad表达式的使用-----------------------------------------------------------------------*/
//unique仅能比较相邻元素
sort(string_words.begin(), string_words.end());
string_words.erase(unique(string_words.begin(), string_words.end()), string_words.end());
sort(string_words.begin(), string_words.end(), [](const string &s1, const string &s2){return s1.size()>s2.size();});
for (const auto &s : string_words)
{
cout << s << " ";
}
cout << endl;
/*lambda参数传输-------------------------------------------------------------------------*/
unsigned int sz = 3;
auto wc = find_if(string_words.begin(), string_words.end(), [sz](const string &s1){return s1.size()< sz ;});
cout << "num = " << wc-string_words.begin() << endl;
auto string_words_beg = string_words.begin();
while(string_words_beg != wc)
{
cout << *string_words_beg++ << " ";
}
cout << endl;
/*lambda值的捕获------------------------------------------------------------------------*/
//值在创建时拷贝，不是在使用时拷贝
{
size_t vt = 100;
auto f = [vt] () {return vt ;}; //创建时将vt拷贝到名为f的可调用对象
vt = 0;
cout << f() << endl;
}
//引用捕获
{
size_t vt = 100;
auto f = [&vt](){return vt ;};
vt = 0;
cout << f() <<endl;
}
/*可变lamdba-------------------------------------------------------------------------*/
//对于一个值被拷贝量，lamdba不能改变其变量；如果想要改变加上mutable
{
size_t vt = 100;
//auto f = [vt] () {return ++vt; }; 不加mutable会提示编译错误
auto f = [vt] () mutable {return ++vt; };
cout << f() <<endl;
}
//如果是引用变量值则可以修改
{
size_t vt = 100;
auto f = [&vt] () {return ++vt ;};
cout << f() << endl;
}
/*指定lamdba返回类型----------------------------------------------------------------*/
//如果lamdba包含任何return之外的语句，则编译器默认返回void
{
vector<int> num = {1, -2, 3, -4, 5, -6, 7, -8, 9};
//负值取绝对值
transform(num.begin(), num.end(), num.begin(), [](const &temp_num){return temp_num > 0 ? temp_num : -temp_num; });
for (const auto &temp_num : num)
{
cout << temp_num << " ";
}
cout << endl;
//指定返回类型， 使用 ->int, 或者包含非return语句编译器报错
transform(num.begin(), num.end(), num.begin(),
[](const &temp_num) ->int
{ if (temp_num % 2 == 0) return temp_num; else return -temp_num ;});
for (const auto &temp_num : num)
{
cout << temp_num << " ";
}
cout << endl;
}
/*bind函数使用---------------------------------------------------------------------------------*/
//check_sized函数第二个参数指定为6，在调用CheckSized时，传入第一个参数即可
auto CheckSized = bind(check_sized, std::placeholders::_1, 6);
string words = "hello";
cout << CheckSized(words) << endl;
auto SortNum = bind(sort_num, 1, 2, 3, std::placeholders::_2, std::placeholders::_1);
SortNum(5, 4);
}