The member functions of class valarray include the size() function, which returns the size of a valarray, and the sum() function, which returns the sum of all elements in a valarray. The functions min() and max() return, respectively, the minimum and maximum values in a valarray.
Class valarray also contains two shift functions. Both functions shift elements a specified number of steps to the left, where the 0th element is defined as the leftmost. The shift() function fills in at the right with 0s or T()s. The cshift() function performs a circular shift or rotation so that the ith element becomes the element at location self.length() - n - i, where i runs from 0 to n, and n is the number of steps to shift. Both functions return a new valarray, but the original is not changed. For example:
int a[5] = {1,2,3,4,5};
std::valarray<int> v(a,5);
std::valarray<int> v2 = v.shift(2); // v2 = {3,4,5,0,0}
v2 = v.cshift(2); // v2 = {3,4,5,1,2}
Class valarray provides two versions of the apply() function. These functions apply a user-specified function to each element in the array. Again, these return a new array with the result leaving the original array unaltered.
Finally, as we noted in the discussion on constructors, valarray has a resize function that allows a program to change the number of elements contained by that array. The original elements, if any, are lost in the process since the function re-initializes all elements in the newly-sized array.