CODEWITHSUNDEEP
c++vector
AutomEng
AutomEng

Reputation: 455

Vector equilibrium point(s) function in C++

So I wanted to clean the rust off my C++ skills and thought I'd start with something fairly simple. An equilibrium point in a vector A of size N is a point K, such that: A[0] + A[1] + ... + A[K−1] = A[K+1] + ... + A[N−2] + A[N−1]. The rationale behind the function algorithm is simple: Check each consecutive element of the vector and compare the sum of the elements before said element with the sum of the elements after it and if they are equal, output the index of that element. While it sounds simple (and I imagine that it is) it turned out to be harder to implement in reality. Here's what the code looks like:

#include <iostream>
#include <vector>

using std::cin;
using std::cout;
using std::endl;

void EquilibriumPoint(std::vector<int> &A);
void VectorPrint(std::vector<int> &V);

void main()
{
    int input;
    std::vector<int> Vect1;
    cout << "Input the vector elements" << endl;
    while (cin >> input)
       Vect1.push_back(input);
    VectorPrint(Vect1);
    EquilibriumPoint(Vect1);
}

void EquilibriumPoint(std::vector<int> &A)
{

    for (int it = 0; it != A.size(); ++it)
    {
        int lowersum = 0;
        int uppersum = 0;
        for (int beg = 0; beg != it; ++beg) lowersum += A[beg];
        for (int end = it + 1; end != A.size(); ++end) uppersum += A[end];
        if (uppersum == lowersum) cout << it;
    }
}

void VectorPrint(std::vector<int> &V)
{
    for (int i = 0; i != V.size(); ++i)
        cout << V[i] << endl;
}

As you can see I threw in a print function also for good measure. The problem is that the program doesn't seem to execute the EquilibriumPoint function. There must be a problem with the logic of the implementation but I can't find it. Do you guys have any suggestions?

Upvotes: 1

Views: 376

Answers (1)

lisu
lisu

Reputation: 2263

cin >> input

always returns true for you - so IMHO you have an endless loop. You need to stop collecting elements at some point, for instance

int input = 1
while (input)
{
    cin >> input;
    Vect1.push_back(input);
}

Will accept all elements that are not zero, when zero arrives, it will end the vector and run your function.

Or you can first input the number of elements (if you want to include zeros), example:

int count;
cin >> count
for (int i = 0; i < count; ++i)
{
  cin >> input;
  Vect1.push_back(input);
}

I didn't check the rest of the code, though. One problem at a time.

Upvotes: 1

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