适用于可负可正整数的超级快读快写

struct IO{
    #define MAXSIZE (1<<20)
    #define isdigit(x) (x>='0'&&x<='9')
    char buf[MAXSIZE],*p1,*p2;
    char pbuf[MAXSIZE],*pp;
    #if DEBUG
    #else
    IO():p1(buf),p2(buf),pp(pbuf) {}
    ~IO() {fwrite(pbuf,1,pp-pbuf,stdout);}
    #endif
    char gc(){
        #if DEBUG 
        return getchar();
        #endif
        if(p1==p2) p2=(p1=buf)+fread(buf,1,MAXSIZE,stdin);
        return p1==p2?' ':*p1++;
    }
    bool blank(char ch){
        return ch==' '||ch=='\n'||ch=='\r'||ch=='\t';
    }
    template <class T>
    void read(T &x){
        double tmp=1;
        bool sign=false;
        x=0;
        char ch=gc();
        for(;!isdigit(ch);ch=gc())
            if(ch=='-') sign=1;
        for(;isdigit(ch);ch=gc()) x=x*10+(ch-'0');
        if(ch=='.')
            for(ch=gc();isdigit(ch);ch=gc())
                tmp/=10.0,x+=tmp*(ch-'0');
        if(sign) x=-x;
    }
    void read(char *s){
        char ch=gc();
        for(;blank(ch);ch=gc());
        for(;!blank(ch);ch=gc()) *s++=ch;
        *s=0;
    }
    void read(char &c) {for(c=gc();blank(c);c=gc());}
    void push(const char &c){
        #if DEBUG 
        putchar(c);
        #else
        if(pp-pbuf==MAXSIZE) fwrite(pbuf,1,MAXSIZE,stdout),pp=pbuf;
        *pp++=c;
        #endif
    }
    template <class T>
    void write(T x){
        if(x<0) x=-x,push('-');
        static T sta[35];
        T top=0;
        do{
          sta[top++]=x%10,x/=10;
        }while(x);
        while(top) push(sta[--top]+'0');
    }
    template <class T>
    void write(T x,char lastChar){
        write(x),push(lastChar);
    }
}io;

调用

int x;
io.read(x);
io.write(x);