What is this C++ function? What is the name of the algorithm?

`void SortArr(int arr[], int n) {`

for (int startIndex = 0; startIndex < n - 1; ++startIndex) {

int smallestIndex = startIndex;

for (int currentIndex = startIndex + 1; currentIndex < n; ++currentIndex) {

if (arr[currentIndex] < arr[smallestIndex]) {

smallestIndex = currentIndex;

}

}

swap(arr[startIndex], arr[smallestIndex]);

}

}