RISTREAM рандом пълнене на инт, double и чар

//файл ristream.h
#include <iostream>
class Ristream{
    std::istream & in;
    unsigned length;
    bool space;
public:
    Ristream(unsigned length=0, bool space=false, std::istream &in =std::cin):
        length(length), space(space), in(in){}
    Ristream& operator >> (int& i){
        i = rand()%100+rand()*100;
        i = (rand()%2==0)?i:-i;
        return *this;
    }
    Ristream& operator >> (unsigned & u){
        u = rand()%100+rand()*100;
        return *this;
    }
    Ristream& operator >> (double& d){
        d = 10.*rand()/RAND_MAX;
        d = (rand()%2==0)?d:-d;
        return *this;
    }
    void set_length(unsigned L){length=L;}
    unsigned get_length()const{return length;}
    void set_space(bool s){space =s;};
    bool get_space()const{return space;}
    Ristream& operator >> (char * str){
        char abc[] = "abcdefghijklmnopqrstuvwxyz    ";
        for(unsigned i=0; i<length; i++)
            str[i] = space?abc[rand()%30]:abc[rand()%26];
        str[length] = '\0';
        return *this;
    }
};