# Re: Sorting two arrays with one call to sort()?

From:
jtorjo2007@yahoo.com
Newsgroups:
comp.lang.c++.moderated
Date:
Thu, 27 Sep 2007 04:10:45 CST
Message-ID:

I think all the comp.lang.c++.moderated replies
were BS! I wasted time on each one of them and it was
a total waste of time...! None of those suggestions
work...the zip iterator was not designed to do what I
existence for my problem) and the other solution is
not that trivial...as it looks...beware...

I compiled and run this using VS2003:

#include <iostream>
#include <algorithm>
#include <assert.h>

using namespace std;
const int N = 10;

template < typename tA, typename tB >
struct double_iterator {
typedef double_iterator<tA,tB> self;
tA* a;
tB* b;
int idx;
double_iterator(tA* _a, tB* _b, int idx = 0) : idx(idx) {
a = _a ;
b = _b ;
};

struct value_type {
tA a; tB b;
tA *pa; tB *pb;
value_type(tA *pa, tB *pb) : pa(pa), pb(pb), a(*pa),
b(*pb) {};
void operator=(value_type other){
*pa = other.a; *pb = other.b;
};
bool operator<(value_type other){
return a < other.a ;
};
};

typedef std::random_access_iterator_tag iterator_category;
typedef int difference_type;
typedef int distance_type;
typedef value_type& reference;
typedef value_type* pointer;

value_type operator*(){ return value_type(a+idx,b+idx); }

bool operator<(const self & other) const {
assert( a == other.a && b == other.b );
return idx < other.idx;
}

bool operator==(const self & other) const {
return a == other.a && b == other.b && idx == other.idx;
}
bool operator!=(const self & other) const {
return !(*this == other);
}
int operator-(const self & other) {
return idx - other.idx;
}
self operator-(int to_del) const {
self ret = *this;
ret.idx -= to_del;
return ret;
}

self operator++(int) {
self temp = *this;
++idx;
return temp;
}
self &operator++() {
++idx;
return *this;
}

self operator--(int) {
self temp = *this;
--idx;
return temp;
}
self &operator--() {
--idx;
return *this;
}
};

template < typename tA, typename tB >
double_iterator<tA,tB> operator+(double_iterator<tA,tB> it, int
return it;
}

template < typename tA, typename tB >
it) {
return it;
}

int main(void){
int A[N];
float B[N];

for (int i = 0; i < N; ++i){
A[i] = rand(); B[i] = A[i] % 10;
cout << "\t" << A[i] << "\t" << B[i] << endl;
}

std::sort(double_iterator<int,float>(A,B),
double_iterator<int,float>(A,B,N));

for (int i = 0; i < N; ++i){
cout << "\t" << A[i] << "\t" << B[i] << endl;
}

return 0;

}

Best,
John

--
http://John.Torjo.com -- C++ expert
.... call me only if you want things done right

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