## How to find the product of vector elements?

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**This question already has answers here**:

If you want to get the product of **any numeric vector of any size**, here's a function that works with any numeric type of vector with the help of templates:

template <class any> long double vectorProduct(vector<any> vec) { long double total = 1; for(any num : vec) { total *= num; } return total; }

**Usage:**

cout << vectorProduct(vec) << endl;

**Product of Vector Elements,** Product of Vector Elements. Description. prod returns the product of all the values present in its arguments. numeric or complex or logical vectors. B = prod(A,vecdim) computes the product based on the dimensions specified in the vector vecdim. For example, if A is a matrix, then prod(A,[1 2]) is the product of all elements in A , since every element of a matrix is contained in the array slice defined by dimensions 1 and 2.

Using `std::accumulate`

, one can do

#include <numeric> // std::accumulate #include <functional> // std::multiplies const auto total = std::accumulate(vec.cbegin(), vec.cend(), 1, std::multiplies<int>{});

By wrapping into a templated function, the code would be more generic

template<typename Type> auto product(const std::vector<Type>& vec, Type init) { return std::accumulate(vec.cbegin(), vec.cend(), init, std::multiplies<Type>{}); }

and call it with

const auto total = product(vec, /*value to be initialized/ started with*/);

**R: Product of Vector Elements,** We can sum the elements of a vector using the sum() function. Similarly, mean() and prod() functions can be used to find the mean and product of the terms. Finding product product of elements in a vector. I am using a vector whose length I want to vary. So supposing the vector is x = [f (1), f (2), f (3), .. f (n)].

With std, you might use `std::accumulate`

:

int product(const std::vector<int>& v) { return std::accumulate(v.begin(), v.end(), 1, std::multiplies<>{}); }

**Find Sum, Mean and Product of Vector in R Programming,** product of all the values in a vector, like sum but with multiplication instead of addition. I expected this to exist already, but if it does I can't find Similarly, mean() and prod() functions can be used to find the mean and product of the terms. Example: Vector Elements Arithmetic > sum(2,7,5) [1] 14 > x [1] 2 NA 3 1 4 > sum(x) # if any element is NA or NaN, result is NA or NaN [1] NA > sum(x, na.rm=TRUE) # this way we can ignore NA and NaN values [1] 10 > mean(x, na.rm=TRUE) [1] 2.5 > prod(x, na.rm=TRUE) [1] 24

Try multiplying each value inside the vector.

for(std::size_t i=0; i<vec.size(); i++) { total *= vec[i]; }

**multiplying all elements of a vector in R,** rm is FALSE an NA value in any of the arguments will cause a value of NA to be returned, otherwise NA values are ignored. See Also. sum , cumprod , cumsum . Next: Write a R program to find Sum, Mean and Product of a Vector, ignore element like NA or NaN. Test your Python skills with w3resource's quiz.

Here is what I would do for your example:

#include <iostream> int main () { int n; std::cin >> n; int total = 1; while(n--) { int temp; std::cin >> temp; total *= temp; } std::cout << "Total: " << total << std::endl; return 0; }

**R: Product of Vector Elements,** The scalar product and the vector product are the two ways of multiplying vectors which see the most application in physics and astronomy. the process which is used in matrix multiplication, where the sum of the products of the elements of a — scalar dot product. Cross ( ) — vector cross product (entered as cross) Norm — norm of a vector. Total — total of elements in a vector. Div — divergence. Curl — curl in any dimension. Vector Space Operations. VectorAngle — angle between two vectors. UnitVector — unit vector along a coordinate direction. Normalize — normalize

**Scalar Product of Vectors,** B = prod(A) returns the products along different dimensions of an array. If A is a vector, prod(A) returns the product of the elements. If A is a matrix, The product of the elements in each row can be obtained by: prod(M,2) = 48 105 72. See Also . I have a one dimensional NumPy array: a = numpy.array([2,3,3]) I would like to have the product of all elements, 18 in this case. The only way I could find to do this would be:

**prod (MATLAB Function Reference),** We define the matrix-vector product only for the case when the number of To calculate the product B, we view B as a bunch of n×1 column vectors lined up Minimum sum of product of elements of pairs of the given array; Maximum product from array such that frequency sum of all repeating elements in product is less than or equal to 2 * k; Find pairs of elements from two different arrays whose product is a perfect square; Product of all the pairs from the given array

**Multiplying matrices and vectors,** Axis or axes along which a product is performed. The default, axis=None, will calculate the product of all the elements in the input array. If axis is negative it Hadamard product of two vectors is very similar to matrix addition, elements corresponding to same row and columns of given vectors/matrices are multiplied together to form a new vector/matrix. It

##### Comments

- If you wanted to print the values in the vector how would you do that?
- You have to access each member of
`vec`

individually. While the class may be called`vector`

, it's name has more to do with the "shape" of the structure, and isn't designed to be handled like a mathematical "vector", or as a 1-dimensional matrix. - Possible duplicate of C++ Multiplying elements in a vector The technique uses
`std::accumulate`

and`std::multiplies`

. - At the level the OP is, you could drop the
`template`

and use`int`

instead of`any`

. Good answer, but might have a bit of a learning curve ;-) - A generic solution should take into account that taking the product will overflow easily, hence the return type should perhaps not be
`any`

. And I agree with Jeffrey, the solution is probably a bit too far for what OP needs - I dont know. I am just saying that it requires a more well tought design if you are really aiming for " any numeric vector of any size"
- I'd pass the vector by
`const`

reference. - I would not name template
`any`

, too confusing with`std::any`

. generic`T`

is fine. - Be careful when using
`1`

. If the type is not`int`

then the results may not be correct. - @NathanOliver Then it's should be generic. Let me update.
- @NathanOliver You are indeed correct that the return type is based on the type of the initial value for the accumulate. I was wrong. I deleted my comment, so it doesn't become misinformation. Thanks for pointing that out. Your cautionary note is well noted!
- @Wyck No problem. It's why I left it as it tends to trip lots of people up.
- Be careful when using
`1`

. If the type is not`int`

then the results may not be correct. - Indeed, as for
`std::accumulate`

with`std::plus`

.