Re: Ranged Integers

Zara <>
Mon, 03 Sep 2007 11:50:21 +0200
On Sun, 2 Sep 2007 17:47:13 -0600, Jerry Coffin <>

In article <>, says...

is there a simple integer type library around that behaves like normal
integers, i.e has all the same operations, but except the value can
only be in a specific range, like 0 to 100, and if the value is
outside of this range, it will throw an exception or assert fail?

This might fill the bill:


Or, pressing it harder:

#include <exception>
#include <iostream>
#include <functional>

template <class T, T lower, T higher, class less=std::less<T> >
class bounded {
    T val_;

    bool check(T const &value) {
        return less()(value, lower) || less()(upper, value);

    void assign(T const &value) {
        if (check(value))
            throw std::domain_error("Out of Range");
        val_ = value;

    explicit bounded(T val) {assign(val);}

    bounded() :val_(
            less()(higher,T())?higher:T()) {}

    bounded(bounded const &init):val_(init.val_) {}

    template<T1,T1 other_lower,T1 other_higher,less1>
           const &init) {assign(init.val_)}

    bounded &operator=(T const &v) { assign(v); return *this; }

    bounded &operator=(bounded const &v) {val_=v.val_; return *this;}

    template<T1,T1 other_lower,T1 other_higher,less1>
        bounded& operator=(
           const &v) {assign(v.val_)}

    operator T() const { return val_; }

    friend std::istream &operator>>(std::istream &is, bounded &b) {
        T temp;
        is >> temp;
        if (b.check(temp))
            b.val_ = temp;
        return is;

Just to have different types for different ranges, and faster
assignment/copy when maintining range.



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