simpleAlternatedSum X50867

Statement

Implement a RECURSIVE function that, given a positive natural $n$ , returns the simple altenated sum $1-2+3-4+\ldots+(-1)^{n+1}\cdot n$ . This is the header:

// Pre: n >= 1
// Post: Returns 1-2+3-4+...+(-1)^(n+1)*n
int simpleAlternatedSum(int n);

Observation

You only need to submit the required procedure; your main program will be ignored.

Observation

Note that we are requesting a RECURSIVE solution.

Sample session

simpleAlternatedSum(1) = 1
simpleAlternatedSum(5) = 3
simpleAlternatedSum(10) = -5
simpleAlternatedSum(533) = 267

Information

Author: PRO1
Language: English
Translator
Original language: Catalan
Other languages: Catalan Spanish
Official solutions: C++
User solutions: C++