C++ - recursion for loop - how to get access to various iterators

[pajczur]

I would like to make recursion in for loop with access to following iterators independently.
I tried to do that, but it looks like nested loop doesn't update its parent iterator. I am not sure what's wrong here:

std::vector<int> it;
 // some code that fill "it" vector
 
 std::vector<int *> iter;
 for(int i=0; i<it.size(); i++)
 {
     iter.push_back(&it(i));
 }
 
 int sweek = 0;
 int dup=0;
 
 // And now call the function which definition is:
 void matrixRecursion()
 {
     int start = sweek;
     int end = matrix[sweek];
 
     for(it(start); it(start)<end; it(start)++)
     {
         if(sweek < it.size()-1)
         {
             sweek++;
             matrixRecursion();
         }
         else
         {
             for(int t=0; t<it.size(); t++)
             {
                 dup += nIndex[*iter[t]];
             }
         }
     }
 }

std::vector<int> it;
 // some code that fill "it" vector

 std::vector<int *> iter;
 for(int i=0; i<it.size(); i++)
 {
     iter.push_back(&it(i));
 }
        
 int sweek = 0;
 int dup=0;
        
 // And now call the function which definition is:
 void matrixRecursion()
 {
     int start = sweek;
     int end = matrix[sweek];

     for(it(start); it(start)<end; it(start)++)
     {
         if(sweek < it.size()-1)
         {
             sweek++;
             matrixRecursion();
         }
         else
         {
             for(int t=0; t<it.size(); t++)
             {
                 dup += nIndex[*iter[t]];
             }
         }
     }
 }

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For example lets say `it.size()` is 3. Then if everything would work as I expect the result should be like that:

for(int i=0; i<matrix[0]; i++)
 {
     for(int j=0; j<matrix[1]; j++)
     {
         for(int k=0; k<matrix[2]; k++)
         {
             dup += nIndex[i] + nIndex[j] + nIndex[k];
         }
     }
 }

for(int i=0; i<matrix[0]; i++)
 {
     for(int j=0; j<matrix[1]; j++)
     {
         for(int k=0; k<matrix[2]; k++)
         {
             dup += nIndex[i] + nIndex[j] + nIndex[k];
         }
     }
 }

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[d_stranz]

for(it(start); it(start)<end; it(start)++)

Maybe you should explain what you think this line of code is supposed to do. std::vector doesn't have an operator()( int ). Even if it did, what do you expect this code to do? "it" is a vector, and even if "it( start )" returned some member of that vector, your for() loop doesn't save it anywhere so it can use it later so the statement is essentially a no-op.

I think you are basically confused about what iterators are and how you use them. In any case, this post is not about Qt, it is basic C++ knowledge and is off-topic for this forum.