C++, Sort One Vector Based On Another One

Question

The best example I\'ve got is that I want to sort Names based on their Score.

vector  Names {\"Karl\", \"Martin\", \"Paul\", \"Jennie\"};
vecto         


        

Answer 1

As already suggested in other answers: Combining the name and the score of each individual is likely the simplest solution.

Generically, this can be achieved with what is sometimes referred to as a "zip" operation: Combining two vectors into a vector of pairs - along with a corresponding "unzip".

Implemented generically, this may look as follows:

#include 
#include 
#include 
#include 
#include 

// Fill the zipped vector with pairs consisting of the
// corresponding elements of a and b. (This assumes 
// that the vectors have equal length)
template 
void zip(
    const std::vector &a, 
    const std::vector &b, 
    std::vector> &zipped)
{
    for(size_t i=0; i
void unzip(
    const std::vector> &zipped, 
    std::vector &a, 
    std::vector &b)
{
    for(size_t i=0; i names {"Karl", "Martin", "Paul", "Jennie"};
    std::vector score {45, 5, 14, 24};

    // Zip the vectors together
    std::vector> zipped;
    zip(names, score, zipped);

    // Sort the vector of pairs
    std::sort(std::begin(zipped), std::end(zipped), 
        [&](const auto& a, const auto& b)
        {
            return a.second > b.second;
        });

    // Write the sorted pairs back to the original vectors
    unzip(zipped, names, score);

    for(size_t i=0; i