你就說有沒有用函數吧

namespace std{
    class istream{}cin;
    class ostream{}cout;
    istream& operator>>(istream& is,int& value){ //函數1
        __builtin_scanf("%d",&value);
        return is;
    }
    ostream& operator<<(ostream& os,const int& value){ //函數2
        __builtin_printf("%d",value);
        return os;
    }
} /*#include<iostream>*/
int main(){ //函數3
    int a,b;
    std::operator>>(std::operator>>(std::cin,a),b);
    //std::cin>>a>>b;
    std::operator<<(std::cout,a+b);
    //std::cout<<a+b;
}