C++ with STL

2.5.1vector存放内置数据类型

#include<vector>
#include<algorithm>
#include<iostream>
#include<algorithm>
using namespace std;

//vecotr容器存放内置数据类型
void myPrint(int val)
{
    cout << val << endl;
}

void test01()
{
    //创建了一个vector容器，数组
    vector<int> v;

    //向容器中插入数据
    v.push_back(10);
    v.push_back(20);
    v.push_back(30);
    v.push_back(40);
    v.push_back(50);

    //    vector<int>::iterator itBegin = v.begin();//起始迭代器 指向容器中第一个元素
    //    vector<int>::iterator itEnd = v.end();//结束迭代器，指向容器中最后一个元素的下一个位置
    //
    //    //第一种遍历方式
    //    while (itBegin != itEnd)
    //    {
    //        cout << *itBegin << endl;
    //        itBegin++;
    //    }

    //第二种遍历方式
    /*for (vector<int>::iterator it = v.begin(); it != v.end(); it++)
    {
        cout << *it << endl;
    }*/

    //第三种遍历方式，利用STL提供遍历算法
    for_each(v.begin(), v.end(), myPrint);
}
int main()
{
    test01();
    return 0;
}

 

2.5.2vector存放自定义数据类型

#include<iostream>
#include<string>
#include<vector>
using namespace std;
//vector容器存放自定义数据类型
class Person
{
public:
    Person(string name, int age)
    {
        this->m_Name = name;
        this->m_Age = age;
    }
    string m_Name;
    int m_Age;
};

void test01()
{
    vector<Person>v;

    Person p1("aaa", 10);
    Person p2("bbb", 20);
    Person p3("ccc", 30);
    Person p4("ddd", 40);
    Person p5("eee", 50);

    //向容器中添加数据
    v.push_back(p1);
    v.push_back(p2);
    v.push_back(p3);
    v.push_back(p4);
    v.push_back(p5);

    //遍历容器中的数据
    for (vector<Person>::iterator it = v.begin(); it != v.end(); it++)
    {
        //cout << "姓名：" << (*it).m_Name << "年龄：" << (*it).m_Age << endl;
        cout << "姓名：" << it->m_Name << "年龄：" << it->m_Age << endl;
    }
}

//存放自定义数据类型 指针
void test02()
{
    vector<Person*>v;

    Person p1("aaa", 10);
    Person p2("bbb", 20);
    Person p3("ccc", 30);
    Person p4("ddd", 40);
    Person p5("eee", 50);

    //向容器中添加数据
    v.push_back(&p1);
    v.push_back(&p2);
    v.push_back(&p3);
    v.push_back(&p4);
    v.push_back(&p5);

    //遍历容器
    for (vector<Person*>::iterator it = v.begin(); it != v.end();it++)
    {
        cout << "姓名：" << (*it)->m_Name << "年龄：" << (*it)->m_Age << endl;
    }

}
int main()
{
    test02();
    system("pause");
}

 

2.5.3vector容器嵌套容器

#include<iostream>
#include<vector>
using namespace std;

//容器嵌套容器
void test01()
{
    vector<vector<int>>v;

    //创建小容器
    vector<int>v1;
    vector<int>v2;
    vector<int>v3;
    vector<int>v4;

    //向容器中添加数据
    for (int i = 0; i < 4; i++)
    {
        v1.push_back(i + 1);
        v2.push_back(i + 2);
        v3.push_back(i + 3);
        v4.push_back(i + 4);
    }

    //将小容器插入到大容器中
    v.push_back(v1);
    v.push_back(v2);
    v.push_back(v3);
    v.push_back(v4);

    //通过大容器，把所有数据遍历一遍
    for (vector<vector<int>>::iterator it = v.begin(); it != v.end(); it++)
    {
        //(*it)----容器 vector<int>
        for (vector<int>::iterator vit = (*it).begin(); vit != (*it).end(); vit++)
        {
            cout << *vit << " ";
        }
        cout << endl;
    }
}

int main()
{
    test01();
    return 0;
}

 

3.1.2string构造函数

#include<iostream>
#include<string>
using namespace std;
//string的构造函数
void test01()
{
    string s1;//默认构造

    const char* str = "hello world";
    string s2(str);

    cout << "s2=" << s2 << endl;

    string s3(s2);
    cout << "s3=" << s2 << endl;

    string s4(10, 'a');
    cout << "s4=" << s4 << endl;
}

int main()
{
    test01();
}

 

3.2.3string赋值操作

#include<iostream>
#include<string>
using namespace std;

void test01()
{
    string str1;
    str1 = "hello world";
    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(10,'w');
    cout << "str7=" << str7 << endl;
}

int main()
{
    test01();
    return 0;
}

 

3.2.4strng字符串拼接

#include<iostream>
#include<string>
using namespace std;
void test01()
{
    string str1 = "我";
    str1 += "爱玩游戏";
    cout << "str1=" << str1 << endl;

    str1 += ':';
    cout << "str1=" << str1 << endl;

    string str2 = "lol dnf";
    str1 += str2;
    cout << "str1=" << str1 << endl;

    string str3 = "i";
    str3.append(" love ");
    cout << "str3=" << str3 << endl;

    str3.append("game abcde", 4);
    cout << "str3=" << str3 << endl;

    str3.append(str2,0,3);//只截取到lol
    str3.append(str2,4,3);//只截取了 dnf 参数2 从哪个位置开始截取，参数3 截取字符个数

    cout << "str3=" << str3 << endl;
}

int main()
{
    test01();
    return 0;
}

 

3.2.5string查找和替换

#include<iostream>
using namespace std;

//字符串的查找和替换

//1.查找

void test01()
{
    string str1 = "abcdefg";
    int pos=str1.find("de");
    if (pos == -1)
    {
        cout << "未找到字符串" << endl;
    }
    cout << "找到字符串，pos=" << pos << endl;

    //rfind和find区别
    //rfind从右往左查找 find从左往右查找
    pos=str1.rfind("de");
    cout << "pos=" << pos << endl;
}
//2.替换
void test02()
{
    string str1 = "adbdefg";
    //从1号位置起，3个字符 替换为“1111”
    str1.replace(1, 3, "1111");
    cout << "str1=" << str1 << endl;
}

int main()
{
    //test01();
    test02();
    return 0;
}

 

3.2.6string字符串比较

#include<iostream>
using namespace std;

//字符串比较

void test01()
{
    string str1 = "hello";
    string str2 = "hello";

    if (str1.compare(str2) == 0)
    {
        cout << "str1等于str2" << endl;
    }
    else if (str1.compare(str2) > 0)
    {
        cout << "str1大于str2" << endl;
    }
    else
    {
        cout << "str2小于str2" << endl;
    }
}
int main()
{
    test01();
    return 0;
}