Question

Problem Statement:

I want to sort an std::vector of a structure using my custom sorting criteria.

The structure is:

struct Node
{
   int x;
   int y;
   float value;
};

The vector is:

std::vector<Node> vec;

My custom sorting criteria is that the vector should first be sorted by y and then by x (just like in Microsoft Excel).

Example:

Input:

x y

5 6
2 4
1 1
1 0
8 10
4 7
7 1
5 4
6 1
1 4
3 10
7 2

Output:

x y

1 0
1 1
6 1
7 1
7 2
1 4
2 4
5 4
5 6
4 7
3 10
8 10

Can the above mentioned sorting be achieved through any of the C++ Standard Library sorting functions? If not, is there any other library which I can use?

Answer 1

Yes, you can do it using std::sort using a comparison function.

bool comparison(const Node& node1, const Node& node2)
{
    if (node1.y < node2.y) return true;
    if (node1.y == node2.y) return node1.x < node2.x;

    return false;
}

int main() {
    std::sort(vec.begin(), vec.end(), comparison);
}