2011. Final Value of Variable After Performing Operations

There is a programming language with only four operations and one variable X:

• ++X and X++ increments the value of the variable X by 1.
• --X and X-- decrements the value of the variable X by 1.

Initially, the value of X is 0.

Given an array of strings operations containing a list of operations, return the final value of X after performing all the operations.

class Solution {
public:
    int finalValueAfterOperations(vector<string>& operations) {
        int res = 0;
        for(auto& o : operations) {
            if(o[1] == '-') res--;
            else res++;
        }
        return res;
    }
};