STL commonly used containers: string, vector, deque
Table of contents
STL commonly used containers: string, vector, deque
1. The basic concept of string
3. String assignment operation
8. string insertion and deletion
9. string substring: intercept a substring from a string
3. Vector assignment operation
5. Vector insertion and deletion
6. Vector data access operation
1. Basic concept of deque container
5. Deque insertion and deletion
1. String container
1. The basic concept of string
2. The constructor of string
- string();//Create a string such as: string str;
- string(const char* s);//Initialize with string s;
- string(const string& str)//Use a string object to initialize another string object
- string(int n,char c)//initialize with n characters c
#include<iostream>
using namespace std;
//容器-string构造函数
/*
string();//创建字符串 例如：string str;
string(const char* s);//使用字符串s初始化;
string(const string& str)//使用一个string对象初始化另外一个string对象
string(int n,char c)//使用n个字符c初始化
*/
void test01()
{
string s1;
const char* str = "hello world";
string s2(str);
cout << "s2 = " << s2 << endl;
string s3(s2);
cout << "s3 = " << s3 << endl;
string s4(10, 'a');
cout << "s4 = " << s4 << endl;
}
int main()
{
test01();
system("pause");
return 0;
}3. String assignment operation
- string& operator=(const char * s); //Char* type string is assigned to the current string
- string& operator=(const string &s); //Assign the string s to the current string
- string& operator=(char *s); //Assign the character s to the current string
- string& assign(const char * s); //char* type string is assigned to the current string
- string& assign(const char * s,int n); //The first n characters of the char* type string are assigned to the current string
- string& assign(const string &s); //Assign the string s to the current string
- string& assign(int n,char c);//Assign n characters c to the current string
#include<iostream>
using namespace std;
//容器-string赋值操作
/*
string& operator=(const char * s); //char* 类型字符串赋值给当前字符串
string& operator=(const string &s); //把字符串s赋值给当前字符串
string& operator=(char *s); //把字符s赋值给当前字符串
string& assign(const char * s); //char* 类型字符串赋值给当前字符串
string& assign(const char * s,int n); //char* 类型字符串前n个字符赋值给当前字符串
string& assign(const string &s); //把字符串s赋值给当前字符串
string& assign(int n,char c);//用n个字符c赋值给当前字符串
*/
void test01()
{
string str1;
str1 = "hello woeld";
cout << "str1 = " << str1 << endl;
string str2;
str2 = str1;
cout << "str2 = " << str2 << endl;
string str3;
str3 = 'a';
cout << "str3 = " << str3 << endl;
string str4;
str4.assign("hello c++");
cout << "str4 = " << str4 << endl;
string str5;
str5.assign("hello c++",5);
cout << "str5 = " << str5 << endl;
string str6;
str6.assign(str5);
cout << "str6 = " << str6 << endl;
string str7;
str7.assign(7, 'd');
cout << "str7 = " << str7 << endl;
}
int main()
{
test01();
system("pause");
return 0;
}4. string string splicing
- string &operator+=(const char *str); //overload += operator
- string &operator+=(const char c); //overload += operator
- string &operator+=(const string &str); //overload += operator
- string &append(const char *s); //Connect the string s to the end of the current string
- string &append(const char *s,int n); //Connect the first n characters of the string s to the end of the current string
- string &append(const string &s); //同operator+=(const string &str)
- string &append(const string &s,int pos,int n); //The n characters starting from pos in the string s are connected to the end of the string
#include<iostream>
using namespace std;
//容器-string+字符串拼接
/*
string &operator+=(const char *str); //重载+=操作符
string &operator+=(const char c); //重载+=操作符
string &operator+=(const string &str); //重载+=操作符
string &append(const char *s); //把字符串s连接到当前字符串结尾
string &append(const char *s,int n); //把字符串s的前n个字符连接到当前字符串结尾
string &append(const string &s); //同operator+=(const string &str)
string &append(const string &s,int pos,int n); //字符串s中从pos开始的n个字符连接到字符串结尾
*/
void test01()
{
string str1 = "我";
str1 += "爱看";
cout << "str1 = " << str1 << endl;
str1 += ':';
cout << "str1 = " << str1 << endl;
string str2 = "My Brilliant Friend";
str1 += str2;
cout << "str1 = " << str1 << endl;
string str3 = "I";
str3.append(" Love Flower!");
cout << "str3 = " << str3 << endl;
str3.append("Lily 123", 5);
cout << "str3 = " << str3 << endl;
//str3.append(str2);
//cout << "str3 = " << str3 << endl;
str3.append(str2, 3, 9);//从位置3开始 往后年截取9个字符+
cout << "str3 = " << str3 << endl;
}
int main()
{
test01();
system("pause");
return 0;
}5. string find and replace
Find: Find whether the specified string exists
Replace: replace the string at the specified position
The difference between rfind and find: rfind looks from right to left, and find looks from left to right
- int find(const string& str, int pos = 0) const; //Find the first occurrence of str, starting from pos
- int find(const char* s, int pos = 0) const; //find the first occurrence of s, starting from pos
- int find(const char* s, int pos, int n) const; //Find the first position of the first n characters of s from position pos
- int find(const char c, int pos = 0) const; //Find the first occurrence of character c
- int rfind(const string& str, int pos = npos) const; //Find the last position of str, starting from pos
- int rfind(const char* s, int pos = npos) const; //find the last occurrence of s, starting from pos
- int rfind(const char* s, int pos, int n) const; //find the last position of the first n characters of s from pos
- int rfind(const char c, int pos = 0) const; //Find the last occurrence of character c
- string& replace(int pos, int n, const string& str); // replace n characters starting from pos with string str
- string& replace(int pos, int n, const char* s); //Replace the n characters starting from pos with the string s
-
#include<iostream> using namespace std; //容器-string字符串查找和替换 void test01() { string str1 = "abcdefg"; int pos = str1.find("de");//返回3 //int pos = str1.find("df");//没有的话，返回-1 if (pos == -1) { cout << "未找到字符串！" << endl; } else { cout << "找到字符串，pos = " << pos << endl; } //rfind 和find的区别 //rfing从右往左找，find是从左往右 pos = str1.rfind("de"); cout << "rfing，pos = " << pos << endl; } //2、替换 void test02() { string str = "abcdefg"; str.replace(1, 3, "1111"); cout << "replace str = " << str << endl; } int main() { test02(); system("pause"); return 0; }
6. string string comparison
Summary: Usually compare whether two characters are equal
#include<iostream>
using namespace std;
//容器-string字符串比较
void test01()
{
string str1 = "hello";
string str2 = "xello";
if (str1.compare(str2) == 0)
{
cout << "str1 等于 str2" << endl;
}
else if(str1.compare(str2) > 0)
{
cout << "str1 小于 str2" << endl;
}
else
{
cout << "str1 大于 str2" << endl;
}
}
int main()
{
test01();
system("pause");
return 0;
}7. string character access
#include<iostream>
using namespace std;
//容器-string字符存取
void test01()
{
string str = "hello";
//1、通过[] 访问单个字符
for (int i = 0; i < str.size(); i++)
{
cout << str[i] << " ";
}
cout << endl;
//通过at 访问当个字符
for (int i = 0; i < str.size(); i++)
{
cout << str.at(i) << " ";
}
cout << endl;
str[0] = 'x';
cout << "str = " << str << endl;
str.at(1) = 'x';
cout << "str = " << str << endl;
}
int main()
{
test01();
system("pause");
return 0;
}8. string insertion and deletion
#include<iostream>
using namespace std;
//容器-string字符串插入和删除
void test01()
{
string str = "hello";
//插入
str.insert(1, "1111");
cout << "str = " << str << endl;
//删除
str.erase(1, 4);
cout << "str = " << str << endl;
string str2 = "World";
str.insert(str.size(), str2);
cout << "str = " << str << endl;
}
int main()
{
test01();
system("pause");
return 0;
}9. string substring: intercept a substring from a string
string substr(int pos = 0, int n=npos)const ;//return a string consisting of n characters starting from pos
#include<iostream>
using namespace std;
//容器-string字符串插入和删除
void test01()
{
string str = "Hello World";
string subStr = str.substr(1, 3);
cout << "subStr = " << subStr << endl;
}
//实用操作
void test02()
{
string email = "[email protected]";
//从邮件地址中 获取 用户名信息
int pos = email.find("@");
cout << pos << endl;
string userName = email.substr(0, pos);
cout << "User Name = " << userName << endl;
}
int main()
{
test02();
system("pause");
return 0;
}Two, vector container
1. Basic concept of vector
Notice:
- This v.end specifies the next element address of the last element
- Single-ended array: the end of the array can be inserted and deleted
2. Vector constructor
#include<iostream>
#include <vector>
using namespace std;
//打印
void printVector(vector<int>&v)
{
for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
void test01()
{
vector<int>v1;//默认构造 无参构造
for (int i = 0; i < 10; i++)
{
v1.push_back(i);
}
printVector(v1);
//通过区间的方式进行构造
vector<int>v2(v1.begin(), v1.end());
printVector(v2);
//n个elem
vector<int>v3(10, 100);//10个100
printVector(v3);
//拷贝构造
vector<int>v4(v3);
printVector(v4);
}
int main()
{
test01();
system("pause");
return 0;
}3. Vector assignment operation
#include<iostream>
#include <vector>
using namespace std;
void printVector(vector<int> &v)
{
for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//vector赋值
void test01()
{
vector<int>v1;
for (int i = 0; i < 10; i++)
{
v1.push_back(i);
}
printVector(v1);
//赋值=
vector<int>v2 = v1;
printVector(v2);
//assign
vector<int>v3;
v3.assign(v1.begin(), v1.end());
printVector(v3);
//n个elem方式赋值
vector<int>v4;
v4.assign(10, 100);
printVector(v4);
}
int main()
{
test01();
system("pause");
return 0;
}4. Vector capacity and size
#include<iostream>
#include <vector>
using namespace std;
void printVector(vector<int>v)
{
for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//vector容量和大小
void test01()
{
vector<int>v1;
for (int i = 0; i < 10; i++)
{
v1.push_back(i);
}
printVector(v1);
if (v1.empty())//为真，代表容器为空，即v1为空
{
cout << "v1为空" << endl;
}
else
{
cout << "v1 不为空" << endl;
cout << "v1的容量：" << v1.capacity() << endl;
cout << "v1的大小：" << v1.size() << endl;
}
//重新指定大小
//v1.resize(15);
//printVector(v1);//如果重写指定的长度比原来长，默认用0填充
v1.resize(15,100);//利用重载版本，可以指定默认值填充，参数2
printVector(v1);
v1.resize(5);//如果重写指定的长度比原来短，超出部分被删除
printVector(v1);
}
int main()
{
test01();
system("pause");
return 0;
}5. Vector insertion and deletion
- push_back tail delete
- pop_back tail plug
- insert insert
- erase delete
- clear empty
#include<iostream>
#include <vector>
using namespace std;
void printVector(vector<int>& v)
{
for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//vector插入和删除
void test01()
{
vector<int>v;
//尾插
v.push_back(10);
v.push_back(20);
v.push_back(30);
v.push_back(40);
v.push_back(50);
printVector(v);
//尾删
v.pop_back();
printVector(v);
//插入
v.insert(v.begin(), 100);//第一个参数是迭代器
printVector(v);
v.insert(v.begin(), 2, 1000);//第一个参数是迭代器
printVector(v);
//删除
v.erase(v.begin());//也是迭代器
printVector(v);
//类似于清空
//v.erase(v.begin(),v.end());//也是迭代器
v.clear();
printVector(v);
}
int main()
{
test01();
system("pause");
return 0;
}6. Vector data access operation
#include<iostream>
#include <vector>
using namespace std;
//vector数据存取
void test01()
{
vector<int>v;
for (int i = 0; i < 10; i++)
{
v.push_back(i);
}
//利用[]访问数组中的元素
for (int i = 0; i < v.size(); i++)
{
cout << v[i] << " ";
}
cout << endl;
//利用at方式访问元素
for (int i = 0; i < v.size(); i++)
{
cout << v.at(i) << " ";
}
cout << endl;
//获取第一个元素
cout << "第一个元素：" << v.front() << endl;
//获取最后一个元素
cout << "最后一个元素：" << v.back() << endl;
}
int main()
{
test01();
system("pause");
return 0;
}7. Vector exchange elements
Function prototype: swap(vec);//Swap vec with its own elements
#include<iostream>
#include <vector>
using namespace std;
//vector互换
void printVector(vector<int>&v)
{
for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//1、基本使用
void test01()
{
vector<int>v1;
for (int i = 0; i < 10; i++)
{
v1.push_back(i);
}
cout<<"交换前：" << endl;
printVector(v1);
vector<int>v2;
for (int i = 10; i > 0; i--)
{
v2.push_back(i);
}
printVector(v2);
//交换后
cout<<"交换后：" << endl;
v1.swap(v2);
printVector(v1);
printVector(v2);
}
//2、实际使用
//巧用swap可以收缩内存空间
void test02()
{
vector<int>v;
for (int i = 0; i < 10000; i++)
{
v.push_back(i);
}
cout << "v的容量为：" << v.capacity() << endl;
cout << "v的大小为：" << v.size() << endl;
v.resize(3);
cout << "resize v的容量为：" << v.capacity() << endl;
cout << "resize v的大小为：" << v.size() << endl;
vector<int>(v).swap(v); //vector<int>(v)是匿名对象 系统在执行完成该句之后 释放
cout << "swap v的容量为：" << v.capacity() << endl;
cout << "swap v的大小为：" << v.size() << endl;
}
int main()
{
test02();
system("pause");
return 0;
}The reason why sawp shrinks memory: After the anonymous object is executed, the system automatically releases it
8. Vector reserved space
Function description: reduce the number of expansions of vector when dynamically expanding capacity
Function prototype: reserve(int,len);//The container reserves the length of len elements, the reserved position is not initialized, and the elements are inaccessible
#include<iostream>
#include <vector>
using namespace std;
//vector预留空间
void test01()
{
vector<int>v;
//利用reserve预留空间
v.reserve(100000);
int num = 0;
int* p = NULL;
for (int i = 0; i < 10; i++)
{
v.push_back(i);
//每次开辟新内存 都会使得首地址变化
if (p != &v[0])
{
p = &v[0];
num++;
}
}
cout << "num = " << num << endl;
}
int main()
{
test01();
system("pause");
return 0;
}Summary: If the amount of data is large, you can use resreve to reserve space from the beginning
Three, deque container
1. Basic concept of deque container
- Insertion and deletion are faster than vector, but access is slower than vector, because vector needs to access the address first and then access the element
- Iterators for deque containers also support random access
2. Deque constructor
#include<iostream>
#include <deque>
using namespace std;
void printDeque(const deque<int>& d)//加const只读容器
{
for (deque<int>::const_iterator it = d.begin(); it != d.end(); it++)
{
//*it = 100;//加const只读容器 容器中的数据不可以修改
cout << *it << " ";
}
cout << endl;
}
//deque构造函数
void test01()
{
deque<int>d1;
for (int i = 0; i < 10; i++)
{
d1.push_back(i);
}
printDeque(d1);
deque<int>d2(d1.begin(), d1.end());
printDeque(d2);
deque<int>d3(10, 100);
printDeque(d3);
deque<int>d4(d3);
printDeque(d4);
}
int main()
{
test01();
system("pause");
return 0;
}3. Deque assignment operation
#include<iostream>
#include <deque>
using namespace std;
void printDeque(deque<int>&d)
{
for (deque<int>::iterator it = d.begin(); it != d.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//deque赋值操作
void test01()
{
deque<int>d1;
for (int i = 0; i < 10; i++)
{
d1.push_back(i);
}
printDeque(d1);
//operator= 赋值
deque<int>d2;
d2 = d1;
printDeque(d2);
//assign
deque<int>d3;
d3.assign(d1.begin(), d1.end());
printDeque(d3);
deque<int>d4(10, 100);
printDeque(d4);
}
int main()
{
test01();
system("pause");
return 0;
}4. Deque size operation
The deque container has no capacity limit and can be expanded infinitely
#include<iostream>
#include <deque>
using namespace std;
void printDeque(deque<int>& d)
{
for (deque<int>::iterator it = d.begin(); it != d.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//deque大小操作
void test01()
{
deque<int>d1;
for (int i = 0; i < 10; i++)
{
d1.push_back(i);
}
printDeque(d1);
if (d1.empty())
{
cout << "d1为空" << endl;
}
else
{
cout << "d1不为空" << endl;
cout << "d1容量：" << d1.size()<<endl;
//deque没有容量的概念
}
d1.resize(15);
//printDeque(d1);
d1.resize(15, 1);
printDeque(d1);
d1.resize(5);
printDeque(d1);
}
int main()
{
test01();
system("pause");
return 0;
}5. Deque insertion and deletion
#include<iostream>
#include <deque>
using namespace std;
void printDeque(const deque<int>& d)//const只读迭代器
{
for (deque<int>::const_iterator it = d.begin(); it != d.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//deque大小操作
void test01()
{
deque<int>d1;
//尾插
d1.push_back(10);
d1.push_back(20);
//头插 200 100 10 20
d1.push_front(100);
d1.push_front(200);
printDeque(d1);
//尾删
d1.pop_back();
//头删
d1.pop_front();
printDeque(d1);
}
//插入insert
void test02()
{
deque<int> d1;
d1.push_back(10);
d1.push_back(20);
d1.push_front(100);
d1.push_front(200);
//200 100 10 20
printDeque(d1);
d1.insert(d1.begin(),1000);
//1000 200 100 10 20
printDeque(d1);
d1.insert(d1.begin(), 2, 11);
//11 11 1000 200 100 10 20
printDeque(d1);
deque<int>d2;
d2.push_back(1);
d2.push_back(2);
d2.push_back(3);
d1.insert(d1.begin(), d2.begin(), d2.end());
//1 2 3 11 11 1000 200 100 10 20
printDeque(d1);
}
void test03()
{
deque<int> d1;
d1.push_back(10);
d1.push_back(20);
d1.push_front(100);
d1.push_front(200);
//删除
deque<int>::iterator it = d1.begin();
it++;
d1.erase(it);
printDeque(d1);
//区间方式删除
//类似于清空
//d1.erase(d1.begin(), d1.end());
//printDeque(d1);
//清空
d1.clear();
printDeque(d1);
}
int main()
{
test03();
system("pause");
return 0;
}6. Deque data storage
#include<iostream>
#include <deque>
using namespace std;
void printDeque(const deque<int>& d)//const只读迭代器
{
for (deque<int>::const_iterator it = d.begin(); it != d.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//deque大小操作
void test01()
{
deque<int>d;
d.push_back(10);
d.push_back(20);
d.push_back(30);
d.push_front(100);
d.push_front(200);
d.push_front(300);
//通过[]方式访问元素
//300 200 100 10 20 30
for (int i = 0; i < d.size(); i++)
{
cout << d[i] << " ";
}
cout << endl;
//通过at的方式
for (int i = 0; i < d.size(); i++)
{
cout << d.at(i) << " ";
}
cout << endl;
cout << "第一个元素为：" << d.front() << endl;
cout << "最后一个元素为：" << d.back() << endl;
}
int main()
{
test01();
system("pause");
return 0;
}7. Deque sorting
#include<iostream>
#include <deque>
using namespace std;
#include<algorithm>
void printDeque(const deque<int>& d)//const只读迭代器
{
for (deque<int>::const_iterator it = d.begin(); it != d.end(); it++)
{
cout << *it << " ";
}
cout << endl;
}
//deque大小操作
void test01()
{
deque<int>d;
d.push_back(10);
d.push_back(20);
d.push_back(30);
d.push_front(100);
d.push_front(200);
d.push_front(300);
//300 200 100 10 20 30
printDeque(d);
//排序 默认排序规则 升序
//对于支持随机访问的迭代器，都可以利用sort算法之间进行排序
//vector容器也可以利用sort排序
sort(d.begin(), d.end());
cout << "排序后结果：" << endl;
printDeque(d);
}
int main()
{
test01();
system("pause");
return 0;
}