Hello I need help with a c++ function for my project involving vectors. Here is the RME for it

//REQUIRES: v is not empty

// p is between 0 and 1, inclusive

//EFFECTS: returns the percentile p of the numbers in v like Microsoft Excel.

// Refer to the Appendix in the spec for the formula to use.

// NOTE: the definition in the wiki article uses indexing from 1. You will

// need to adapt it to use indexing from 0.

double percentile(std::vector<double> v, double p);