企业数字化转型今日头条搜索优化
目录
什么是STL？
vector容器
构造函数
赋值操作
vector容量和大小
vector存放内置数据类型
vector存放自定义数据类型
存放指针
vector容器嵌套容器
string容器
构造函数
赋值操作
字符串拼接
查找和替换
string字符串比较
string字符存取
string插入和删除
string子串
什么是STL？
stl中的东西可以重复利用，stl是为了建立数据结构与算法的一套标准
stl分为容器，算法，迭代器
stl六大组件：容器，算法，迭代器，仿函数，适配器，空间配置器
vector容器
可以理解为比较强大的数组
构造函数
#include<iostream>
#include<vector>
using namespace std;
void print(vector<int>& a) {for (int i = 0; i < a.size (); i++) {cout << a[i] << " ";}cout << endl;
}
int main() {//默认构造vector<int> a;for (int i = 0; i < 10; i++) {a.push_back(i);}print(a);//区间构造vector<int> b(a.begin(), a.end());print(b);//n个elem方式构造vector<int> c(10, 100);print(c);//拷贝构造vector<int> d(a);print(d);return 0;
} 
赋值操作
#include<iostream>
#include<vector>
using namespace std;
void print(vector<int>& a) {for (int i = 0; i < a.size(); i++) {cout << a[i] << " ";}cout << endl;
}
int main() {vector<int> a;for (int i = 0; i < 10; i++) {a.push_back(i);}print(a);vector<int> b;b = a;print(b);//assignvector<int> c;c.assign(a.begin(), a.end());print(c);//n个elemvector<int> d;d.assign(10, 100);print(d);return 0;
}
vector容量和大小
#include<vector>
#include<iostream>
using namespace std;
void p(vector<int>& a) {for (int i = 0; i < a.size(); i++) {cout << a[i] << " ";}cout << endl;
}
int main() {vector<int> a;for (int i = 0; i < 10; i++) {a.push_back(i);}p(a);if (a.empty()) {cout << "空" << endl;}else {cout << "不空" << endl;cout << "容量为：" << a.capacity() << endl;cout << "大小为：" << a.size() << endl;}//重新指定大小a.resize(15,100);p(a);//长度过大默认用0填充，如果指定数字则用指定数字填充a.resize(5);p(a);//超出部分删除return 0;
} 
vector存放内置数据类型
#include<iostream>
#include<algorithm>//算法头文件
#include<vector>//该容器的头文件
using namespace std;
//第三种遍历方式的函数
void print(int t) {cout << t << endl;
}
int main() {//创建容器vector<int> a;//插入数据a.push_back(10);a.push_back(20);a.push_back(30);//通过迭代器访问数据//起始迭代器，指向第一个元素vector<int>::iterator itBegin = a.begin();//结束迭代器，最后一个元素的下一个位置vector<int>::iterator itEnd = a.end();//遍历//第一种方式(复杂)while (itBegin != itEnd) {cout << *itBegin << endl;itBegin++;}//第二种方式for (vector<int> ::iterator it = a.begin(); it != a.end(); it++) {cout << *it << endl;}//第三种方式(STL遍历算法)for_each(a.begin(), a.end(),print);return 0;
}vector存放自定义数据类型
#include<iostream>
#include<algorithm>
#include<vector>
#include<cstring>
using namespace std;
class person {
public:person(string name, int age) {this->m_Name = name;this->m_Age = age;}string m_Name;int m_Age;
};
int main() {vector<person> a;person p1("aaa", 10);person p2("bbb", 20);person p3("ccc", 30);//放入数据a.push_back(p1);a.push_back(p2);a.push_back(p3);//遍历for (vector<person> ::iterator it = a.begin(); it != a.end(); it++) {cout << "姓名：" << (*it).m_Name << " " << (*it).m_Age << endl;}return 0;
}
存放指针
#include<iostream>
#include<algorithm>
#include<vector>
#include<cstring>
using namespace std;
class person {
public:person(string name, int age) {this->m_Name = name;this->m_Age = age;}string m_Name;int m_Age;
};
int main() {vector<person*> a;person p1("aaa", 10);person p2("bbb", 20);person p3("ccc", 30);//放入数据a.push_back(&p1);a.push_back(&p2);a.push_back(&p3);//遍历for (vector<person *> ::iterator it = a.begin(); it != a.end(); it++) {cout << "姓名：" << (*it)->m_Name << " " << (*it)->m_Age << endl;}return 0;
}
vector容器嵌套容器
类似二维数组
#include<iostream>
#include<algorithm>
#include<vector>
using namespace std;
int main() {vector<vector<int>> a;//创建小容器vector<int> a1;vector<int> a2;vector<int> a3;//向小容器中添加数据for (int i = 0; i < 3; i++) {a1.push_back(i + 1);a2.push_back(i + 2);a3.push_back(i + 3);}//小容器放入大容器a.push_back(a1);a.push_back(a2);a.push_back(a3);//通过大容器把所有数据遍历一遍for (vector<vector<int>> ::iterator it = a.begin(); it != a.end(); it++) {for (vector<int> ::iterator vit = (*it).begin(); vit != (*it).end(); vit++) {cout << (*vit) << " ";}cout << endl;}return 0;
}
string容器
string可以看成c++的字符串,string本质上是一个类
构造函数
#include<iostream>
#include<string>
using namespace std;
int main() {//默认构造string s1;//使用字符串s初始化const char* str = "hello world";string s2(str);cout << "s2=" << s2 << endl;//拷贝构造string s3(s2);cout << "s3=" << s3 << endl;//用n个字符初始化string s4(10, 'a');cout << "s4=" << s4 << endl;return 0;
}
赋值操作
#include<iostream>
#include<string>
using namespace std;
int main() {//char*类型字符串，赋值给当前的字符串string s1 = "hello";cout << "s1=" << s1 << endl;//把字符串s赋值给当前的字符串string s2 = s1;cout << "s2=" << s2 << endl;//字符赋值给当前的字符串string s3 = "a";cout << "s3=" << s3 << endl;//把字符串s赋值给当前的字符串string s4;s4.assign("c++");cout << "s4=" << s4 << endl;//把字符串s的前n个字符赋给当前字符串string s5;s5.assign("c++", 2);cout << "s5=" << s5 << endl;//把字符串s赋值给当前的字符串string s6;s6.assign(s5);cout << "s6=" << s6 << endl;//用n个字符c赋给当前字符串string s7;s7.assign(10, 'W');cout << "s7=" << s7 << endl;return 0;
} 
字符串拼接
#include<iostream>
#include<string>
using namespace std;
int main() {string s1 = "我";s1 += "爱玩游戏";cout << "s1=" << s1 << endl;s1 += ':';cout << "s1=" << s1 << endl;string s2 = "LOL";s1 += s2;cout << "s1=" << s1 << endl;string s3 = "I ";s3.append("love ");cout << "s3=" << s3 << endl;s3.append("game abcde", 4);//前4个cout << "s3=" << s3 << endl;s3.append(s2);cout << "s3=" << s3 << endl;s3.append(s2, 0, 2);//截取s2中的字符，第0个开始，截取2个cout << "s3=" << s3 << endl;return 0;
}
查找和替换
#include<iostream>
#include<string>
using namespace std;
int main() {//查找string s1 = "abcdefgde";int pos = s1.find("de");cout << pos << endl;//d的位置pos = s1.rfind("de");cout << pos << endl;//find从左往右查，rfind从右往左查//替换string s2 = "abcdefg";s2.replace(1, 3, "11111111");//1~3位置全部替换为11111111cout << s2 << endl;return 0;
} 
string字符串比较
#include<iostream>
#include<string>
using namespace std;
int main() {//比较方式：ASC||码//=返回0//>返回1//<返回-1string s1 = "xello";string s2 = "hello";if (s1.compare(s2) == 0) {cout << "s1=s2" << endl;}else if (s1.compare(s2) > 0) {cout << "s1>s2" << endl;}else {cout << "s1<s2" << endl;}return 0;
} 
string字符存取
#include<iostream>
#include<string>
using namespace std;
int main() {string s1 = "hello";cout << s1 << endl;//通过[]访问单独字符for (int i = 0; i < s1.size(); i++) {cout << s1[i] << " ";}cout << endl;//通过at方式访问单个字符for (int i = 0; i < s1.size(); i++) {cout << s1.at(i) << " ";}cout << endl;//修改单个字符s1[0] = 'x';cout << s1 << endl;return 0;
}
string插入和删除
#include<iostream>
#include<string>
using namespace std;
int main() {string s = "hello";//插入s.insert(1, "111");cout << s << endl;//删除s.erase(1, 3);cout << s << endl;return 0;
}
string子串
#include<iostream>
#include<string>
using namespace std;
int main() {string s = "abcdef";string sub = s.substr(1, 3);cout << sub << endl;//实用操作string email = "zhangsan@sina.com";int pos=email.find("@");string userName = email.substr(0, pos);cout << userName << endl;return 0;
}
未完待续。。。。。。。。。。。。。。。
