这个快读在$CSP$能用吗?

namespace io
{
    int op;char ch;
    template<class I>
    void gi(I &w)
    {
        ch=getchar(),op=1,w=0;
        while(!isdigit(ch)){if(ch=='-') op=-1;ch=getchar();}
        while(isdigit(ch)){w=w*10+ch-'0';ch=getchar();}
        w*=op;
    }
    template<typename T,typename... Args>
    void gi(T& t,Args&... args){gi(t);gi(args...);}
}
using io::gi;