CODEWITHSUNDEEP
c++for-loop
Daniel Duque
Daniel Duque

Reputation: 159

How can I circle back to the a starting point using a for loop?

I have a std::vector<std::unique_ptr<object>> myObjects_ptrs. I need to, starting in one of my objects, circle back again to where I started.

I am doing this as follows:

while(true)
{
    for(int i = 0; i < myObjects_ptrs.size(); ++i)
    {
        myObjects_ptr[i]->doSomething();
        //and here I need to circle back
        for(int j = i + 1; j < myObjects_ptr.size(); ++j)
        {
            //do some things with each other object
        }
        for(int j = 0; j < i; ++j)
        {
            //do the same things with the rest of the objects
        }
    }
}

Is this the standard way of doing that? My problem is that once I detect something, then I dont need to keep going around. For example if I find something during the first loop then there is no need to go through the second loop. I con solve this by adding an extra if before the second loop; but is there a better way?

Upvotes: 1

Views: 311

Answers (2)

Sid S
Sid S

Reputation: 6125

You could replace the two inner loops with something like this:

for(int j = i + 1;; j++)
{
    j %= myObjects_ptr.size();
    if (j == i)
    {
        break;
    }
    // Do stuff
}

Upvotes: 1

nitronoid
nitronoid

Reputation: 1609

You could use a modulus, i.e. the two inner loops would become:

int numObjects = myObjects_ptr.size();
for (int j = i + 1; j < numObjects + i + 1; ++j)
{
  // Get object
  auto& obj = myObjects_ptr[j % numObjects];
}

Upvotes: 1

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