std::sample not found in Point Cloud Project - c++

Question

I am trying to implement RANSAC in a PCL project. I am getting the following 3 errors. For the first error, I understand that C++17 needs to be enabled. However, I have no clue what the other 2 errors mean.
I have tried using std::experimental::sample but that doesn't
work either.
#include "../../render/render.h"
#include <unordered_set>
#include "../../processPointClouds.h"
// using templates for processPointClouds so also include .cpp to help linker
#include "../../processPointClouds.cpp"
#include <random>
#include <algorithm>
#include <experimental/algorithm>
std::unordered_set<int> Ransac(pcl::PointCloud<pcl::PointXYZ>::Ptr cloud, int maxIterations, float distanceTol)
{
std::unordered_set<int> inliersResult;
srand(time(NULL));
while(maxIterations--) {
std::unordered_set<int> inliers; // store the inliers here in each iteration
int sample_size {2};
std::vector<pcl::PointXYZ> sample (sample_size);
std::sample(cloud->points.begin(), cloud->points.end(), std::back_inserter(sample),
sample_size, std::mt19937{std::random_device{}()});
// fit a line ax + by+ c = 0 to the points in sample using (y0−y1)x+(x1−x0)y+(x0∗y1−x1∗y0)=0
double x0 {sample.at(0).x}, y0 {sample.at(0).y}, x1 {sample.at(1).x}, y1 {sample.at(1).y};
double a {y0 - y1};
double b {x1 - x0};
double c {x0 * y1 - x1 * y0};
// find the distance to this line for all points in the cloud. If the distance is less than
// distanceTol at the index of the point to inliers
for(auto& point: cloud->points) {
double distance = fabs(a * point.x - b * point.y - c) / sqrt(std::pow(a, 2) + std::pow(b, 2));
if (distance < distanceTol) {
// add the index of the point to inliers
auto index = std::find(cloud->points.begin(), cloud->points.end(), point);
inliers.emplace(index);
}
}
if (inliers.size() > inliersResult.size()) { inliersResult = inliers; }
}
return inliersResult;
}
Here are the errors:
error: no member named 'sample' in namespace 'std'
std::sample(cloud->points.begin(), cloud->points.end(), std::back_inserter(sample),
/Library/Developer/CommandLineTools/usr/include/c++/v1/algorithm:999:22: error: invalid operands to binary expression ('pcl::PointXYZ' and 'const pcl::PointXYZ')
if (*__first == __value_)
/Library/Developer/CommandLineTools/usr/include/c++/v1/memory:1825:31: error: no viable conversion from 'std::__1::__wrap_iter<pcl::PointXYZ *>' to 'int'
::new((void*)__p) _Up(_VSTD::forward<_Args>(__args)...);