Question

I know how to fill an std::vector with non-trivial initial values, e.g. sequence numbers:

void IndexArray( unsigned int length, std::vector<unsigned int>& v ) {     v.resize(length);     for ( unsigned int i = 0; i < length; ++i )     {         v[i] = i;     } } 

But this is a for-loop. Is there an elegant way to do this with less lines of code using stl functionality (and not using Boost)?

Answer 1

You can use the generate algorithm, for a more general way of filling up containers:

#include <iostream> #include <algorithm> #include <vector>  struct c_unique {    int current;    c_unique() {current=0;}    int operator()() {return ++current;} } UniqueNumber;   int main () {   vector<int> myvector (8);   generate (myvector.begin(), myvector.end(), UniqueNumber);    cout << '\nmyvector contains:';   for (vector<int>::iterator it=myvector.begin(); it!=myvector.end(); ++it)     cout << ' ' << *it;    cout << endl;    return 0; } 

This was shamelessly lifted and edited from cplusplusreference.