Hello I am pretty new to c++ and I am trying to implement a small program that iterates over a 2d vector backwards and adds the value of the vector to points.

If the points have already been added then I want to overwrite the value of the vector with 99.

So for example if number of climbs is four then add the of the program points should have the value 5 and the vector should look like this at the end

```
{1, 1 ,1},
{99, 1, 1},
{99(should start here), 99, 99}
```

But I keep getting a segmentation fault and I don’t know whether I am iterating the vector backwards incorrectly.

Could someone help me out, is this even the right approach?

Thanks in advance.

This is my full code

```
#include <iostream>
#include <vector>
using namespace std;
int main()
{
vector<vector<int>> vect
{ {3}, //finish here
{1, 1 ,1},
{2, 1, 1},
{1, 1, 1} //start here
};
int points = 0;
for (int i = 0; i < vect.size(); i++)
{
for (int j = 0; j < vect[i].size(); j++)
{
cout << vect[i][j] << " ";
}
cout << endl;
}
int visited = 99;
int number_of_climbs = 4;
for(int i = 4; i >= 0; i--)
for (int j = 0; j < number_of_climbs; j++)
{
if(vect[i][j] != 99)
{
points += vect[i][j];
vect[i][j] = 99;;
continue;
}
}
return 0;
}
```

Source: Windows Questions C++