C++ STL

1.Vector 中符合数据类型，指针的存储，出现次数的统计

#include<iostream>
#include<algorithm>
#include<vector>
const int SIZE=40;
using namespace std;
typedef struct Teacher
{
    int age;
    int name[SIZE];
}Teacher;
void vector_int()
{
    vector<int> vec;
    vec.push_back(-1);
    vec.push_back(1);
    vec.push_back(3);
    vec.push_back(5);
    for(vector<int>::iterator it=vec.begin();it!=vec.end();it++)
    {
        cout<<*it<<" ";
    }
    cout<<endl;    
    int sum=count(vec.begin(),vec.end(),3);
    cout<<"count(3)="<<sum<<endl;
}
//复合数据类型 存储
void vector_teacher()
{
    Teacher t1,t2,t3;
    t1.age=t2.age=t3.age=10;
    
    vector<Teacher> vec;
    vec.push_back(t1);
    vec.push_back(t2);
    vec.push_back(t3);
    for(vector<Teacher>::iterator it=vec.begin();it!=vec.end();it++)
    {
        cout<<"age ,"<<it->age<<" ,name"<<it->name<<endl;
    }    
    cout<<endl; 
}
//Vector里面储存指针，取出的时候首先要解引用
void vector_teacher_pro()
{
    Teacher t1,t2,t3;
    t1.age=t2.age=t3.age=10;
    
    vector<Teacher*> vec;
    vec.push_back(&t1);
    vec.push_back(&t2);
    vec.push_back(&t3);
    for(vector<Teacher*>::iterator it=vec.begin();it!=vec.end();it++)
    {
        cout<<"age ,"<<(*it)->age<<" ,name"<<(*it)->name<<endl;
    }    
    cout<<endl; 
}
int main()
{
    vector_int();
    vector_teacher();
    vector_teacher_pro();    
    return 0;
} 

 2.String的常用操作

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;
//string的初始化
void string_init()
{
    string s1 = "aaaa";
    string s2("bbbb");
    string s3 = s2; //通过拷贝构造函数 来初始化对象s3
    string s4(10, 'a');

    cout << "s1:" << s1 << endl;
    cout << "s2:" << s2 << endl;
    cout << "s3:" << s3 << endl;
    cout << "s4:" << s4 << endl;
}

//string的 遍历
void string_show()
{
    string s1 = "abcdefg";
    //1 数组方式
    for (int i=0; i<s1.length(); i++)
    {
        cout << s1[i] << " ";
    }
    cout << endl;
    //2 迭代器
    for (string::iterator it = s1.begin(); it != s1.end(); it++ )
    {
        cout << *it << " ";
    }
    cout << endl;
    //用at[i]会抛出异常
    try
    {
        for (int i=0; i<s1.length() + 3; i++)
        {
            cout << s1.at(i) << " ";  //抛出异常
        }
    }
    catch ( ... )
    {
        cout << "发生异常\n" ;
    }

    cout << "at之后" << endl;
    /*
    try
    {
        for (int i=0; i<s1.length() + 3; i++)
        {
            cout << s1[i] << " "; //出现错误 不向外面抛出异常 引起程序的中断
        }
    }
    catch ( ... )
    {
        cout << "发生异常\n" ;
    }
    */    
}

//字符指针和string的转换
void string_char()
{
    string s1 = "aaabbbb";

    //1 s1===>char *
    //printf("s1:%s \n", s1.c_str());

    //2 char *====>sting 


    //3 s1的内容 copy buf中
    //char buf1[128] = {0};
    //s1.copy(buf1, 3, 0);  //注意 只给你copy3个字符 不会变成C风格的字符串
    //cout << "buf1:" << buf1 << endl; 
}

//字符串的 连接
void string_append()
{
    string s1 = "aaa";
    string s2 = "bbb";
    s1 = s1 + s2;
    cout << "s1:" << s1 << endl;
    string s3 = "333";
    string s4 = "444";
    s3.append(s4);
    cout << "s3:" << s3 << endl;
}
//字符串的查找和替换
void string_find_replace()
{
    string s1 = "wbm hello wbm 111  wbm 222  wbm 333 ";
    //             ▲
    //第一次 出现wbm index

    int index = s1.find("wbm", 0); //位置下标 从0开始
    cout << "index: " << index << endl;

    //案例1 求wbm出现的次数 每一次出现的数组下标
    int offindex = s1.find("wbm", 0);
    while (offindex != string::npos)
    {
        cout << "offindex:" << offindex << endl;
        offindex = offindex + 1;
        offindex = s1.find("wbm", offindex); //wang bao ming 
    }

    //案例2  把小写wbm===>WBM

    string s3 = "aaa  bbb ccc";
    s3.replace(0, 3, "AAA");
    cout << "s3" << s3 << endl;

    offindex = s1.find("wbm", 0);
    while (offindex != string::npos)
    {
        cout << "offindex:" << offindex << endl;
        s1.replace(offindex,3, "WBM");
        offindex = offindex + 1;
        offindex = s1.find("wbm", offindex); //
    }
    cout << "s1替换后的结果: " << s1 << endl;
}


//截断（区间删除）和插入
void string_erase_insert()
{
    string s1 = "hello1 hello2 hello1";
    string::iterator it = find(s1.begin(), s1.end(), 'l');
    if (it != s1.end() )
    {
        s1.erase(it);
    }
    cout << "s1删除l以后的结果:" << s1 << endl;

    s1.erase(s1.begin(), s1.end() );
    cout << "s1全部删除:" << s1 << endl;
    cout << "s1长度 " << s1.length() << endl;

    string s2 = "BBB";

    s2.insert(0, "AAA"); // 头插法
    s2.insert(s2.length(), "CCC");
    cout << s2 << endl;
}

void string_transform()
{
    string s1 = "AAAbbb";
    //1函数的入口地址 2函数对象 3预定义的函数对象
    transform(s1.begin(), s1.end(),s1.begin(), ::toupper);
    cout << "s1" << s1 << endl;

    string s2 = "AAAbbb";
    transform(s2.begin(), s2.end(), s2.begin(), ::tolower);
    cout << "s2:" << s2 << endl;
}
int main()
{
    string_init();
    string_show();
    string_char();
    string_append();
    string_find_replace();
    string_erase_insert();
    string_transform();
    return 0;
}