c++语法笔记

STL

set

#include<bits/stdc++.h>
using namespace std;
int main() {
    set<int>s;
    s.insert(1); 
    s.insert(3); 
    s.insert(5);
    for(auto p=s.begin();p!=s.end();p++) 
        printf("%d ",(*p));
    puts(""); 
    //1 3 5 
    for(auto p=s.rbegin();p!=s.rend();p++) 
        printf("%d ",(*p));
    puts("");
    //5 3 1 
    printf("%d",(int)s.size()); 
    //3
    //注意size返回无符号类型，做减法记得强转int
}

cmath

https://blog.csdn.net/qq_42848319/article/details/121055852