puts(““)；

puts()函数会在字符串末尾自动的添加换行符

所以puts(""); 等价于 cout << endl;

#include<bits/stdc++.h>
using namespace std;
int main(){
	cout << "hello";
	puts("");
	cout << "world";
	cout << endl << "------" << endl;
	cout << "hello";
	cout << endl;
	cout << "world";
}