selectionSort with std::function as parameter in c++

Question

class MySort
{
void bubble(std::vector<int> &vec, std::function<int(int,int)> func)
         { ... } //tihs works

void selectionSort(std::vector<int> &vec, std::function<int(int,int)> func)
         {
             int vecSize=vec.size();
             int i, j, min_idx;
             int temp;
             for (i = 0; i < vecSize-1; i++)  
             {  
                 min_idx = i;  
                 for (j = i+1; j < vecSize; j++)  
                 if(func(vec[j],vec[min_idx]) < 0)
                 min_idx = j;

                 temp = vec[min_idx];
                 vec[min_idx] = vec[i];
                 vec[i] = temp;  
             }
         }
};

I have another MyData class :

class MyData
{
     std::vector<int> t_;
    
     int sortNormal2(int first, int sec)
    {
        return first > sec;
    }

public :
       MyData(std::vector<int> t)
        {
            std::copy(t.begin(),t.end(),back_inserter(t_));
        }

        void sortNormal(std::string choice)
        {
            MySort s;
            auto sort= std::bind(&MyData::sortNormal2,this,std::placeholders::_1, std::placeholders::_2);
            if(choice == "bubbleSort")
            {
                std::cout<<"BubbleSort : "<<std::endl;
                s.bubble(t_, sort);
            }
            else 
            {
                std::cout<<"SelectionSort : "<<std::endl;
                s.selectionSort(t_, sort);
            }
            
        }

Above, i have a function which sort normal and has as a parameter a string.I have use bind and if the choise is bubbleSort it works ok ,but if the choice is another string, it doesn't work , it prints the vector table as normal, not sorted And main looks like this :

std::vector<int> table{ 244, 57, 78, 331, 9, 212, 6};
    MyData data(table);
    data.printVec();
    std::cout<<std::endl;
    data.sortNormal("bubbleSort"); //here if instead of buubleSort i type another string, it doesn't work 
    data.printVec();

Have anyone any idea why this algorithm is not ok? It does nothing and I cannot figure out what is wrong.

Answer 1

You test against being less than zero:

if(func(vec[j],vec[min_idx]) < 0)

But your actual function can only return 0 or 1:

int sortNormal2(int first, int sec)
{
    return first > sec;
}

So the if branch will never be taken.