STL简介

容器类

algorithm中的函数

#include<algorithm>
using namespace std;

一些示例

queue

#include<iostream>
#include<queue>
using namespace std;
/*push(); pop(); empty(); size()*/
/*queue: front(), back();*/
/*priority_queue && stack: top()*/
struct fruite
{
    string name;
    double price;

    /*overloading '>' is prohibited*/
    friend bool operator < (fruite a, fruite b)
    {
        return a.price < b.price;
    }
};

int main()
{
    /*queue*/
    queue<int> q;
    if(q.empty() == true) cout<<"Queue is Empty!\n";
    else cout<<"Queue is not Empty!\n";
    for(int i = 0; i < 5; i++)
        q.push(i);
    cout<<q.front()<<endl;
    cout<<q.back()<<endl;

    while(q.empty() != true)
        q.pop();
    
    cout<<q.size()<<endl;

    cout<<"-----"<<endl;
    /*priority_queue*/
    priority_queue<int> p; 
        // priority_queue<int, vectoe<int>, less<int>) p;
        // priority_queue<int, vector<int>, greater<int>> p;
    p.push(1);
    p.push(10);
    p.push(7);
    p.push(6);
    cout<<"size = "<<p.size()<<endl;
    cout<<p.top()<<endl;
    
    p.pop();
    cout<<p.top()<<endl;
    cout<<"-----"<<endl;
    
    /*Overload operator '<'*/
    priority_queue<fruite> f;
    struct fruite f1, f2, f3;
    if(f.empty() == true) cout<<"f is Empty!"<<endl;

    f1.name = "Apple";
    f1.price = 4.3;
    f2.name = "Banana";
    f2.price = 2.3;
    f3.name = "Grape";
    f3.price = 5.0;
    f.push(f1);
    f.push(f2);
    f.push(f3);
    cout<<f.top().name<<endl;
}

string

#include<iostream>
#include<string>
#include<string.h>
using namespace std;
int main()
{
    string s = "abc";
    cin>>s;
    cout<<s;
    printf("\n");

    string::iterator it;
    /*it左闭右开区间：[ s.begin(), s.end() )*/
    /*相关函数都遵循左闭右开原则*/
    for(it = s.begin(); it < s.end(); it++)
        printf("%c ", *it);
    printf("\n");

    for(int i = 0; i < s.length(); i++)
        printf("%c ", s[i]);
    printf("\n");

    string str1="hello", str2=" everyone!", str3;
    str3 = str1 + str2;
    cout<<str3<<endl;
    if(str1>str2) cout<<"str1>str2"<<endl;

    /*1. insert()*/
    str1 = "abcde"; str2 = "fghij";
        /*insert(pos, str2)*/
    str1.insert(5, str2);
    cout<<str1<<endl;

    str1 = "abcde";
        /*insert(it, it1, int2)*/
    str1.insert(str1.end(), str2.begin(), str2.begin()+2);
    cout<<str1<<endl;

    /*2. erase()*/
    str1 = "abcde";
        /*erase(it)*/
    str1.erase(str1.begin()); /*bcde*/
    cout<<str1<<endl;
        /*erase(it1, it2)*/
    str1.erase(str1.begin()+2, str1.end()); /*bc*/
    cout<<str1<<endl;
        /*erase(pos, len)*/
    str1 = "abcde";
    str1.erase(1, 3);
    cout<<str1<<endl;

    /*3. substr(pos, len)*/
    str1 = "abcde";
    cout<<str1.substr(0,4)<<endl;

    /*4. find()*/
    str1 = "Thank you for your smlie!";
    str2 = "you";
    str3 = "me";
        /*find(str2)*/
    if(str1.find(str2) != string::npos)
        cout<<str1.find(str2)<<endl;
    if(str1.find(str2, 7) != string::npos)
        cout<<str1.find(str2, 7)<<endl;
        /*find(pos, str2)*/
    if(str1.find(str3) != string::npos)
        cout<<str1.find(str3)<<endl;
    else
        cout<<"I don't know where is 'str3'."<<endl;

    /*5. replace()*/
    str1 = "Maybe you will turn around.";
    str2 = "will not";
    str3 = "Surely";
        /*replace(pos,len,str2)*/
    str1.replace(10,4,str2);
    cout<<str1<<endl;
        /*replace(it1,it2,str2)*/
    str1.replace(str1.begin(), str1.begin()+5, str3);
    cout<<str1<<endl;
}

reverse

#include<stdio.h>
#include<algorithm>
using namespace std;
int main()
{
    int a[10] = {10,11,12,13,14,15};
    reverse(a, a+4);
    for(int i = 0; i < 6; i++)
        printf("%d ", a[i]);
}

sort

#include<stdio.h>
#include<algorithm>
using namespace std;
#define n 7
bool cmp(int a, int b)
{
    return a > b;
}
int main()
{
    int i,j,k;
    int a[7] = {3,23,4,42,43,12,34};
    char s[7] = {'a','c','q','e','w','h','e'};
    sort(a,a+n,cmp);
    sort(s,s+n);
    for(i = 0; i < 7; i++)
    printf("%d ", a[i]);
    printf("\n");
    for(i = 0; i < 7; i++)
    printf("%c ", s[i]);
}

cmp函数

//从大到小排序
bool cmp(int a, int b) return a > b;
bool cmp(char a, char b) return a > b;
//结构体数组排序
/*struct node包含x,y两个成员*/
bool cmp(node a, node b) return a.x > b.x;
/*若a.x == b.x则比较y*/
bool cmp(node a, node b)
{
    if(a.x != a.x) return a.x > b.x;
    else    return a.y > b.y;
}