我错过了什么吗？

Question

I am trying to solve a problem on a website and it won't let me through although after trying with examples of my own it works perfectly, so I assume there has to be a case where it won't work and I can't seem to find such.

The problem is as follows: The first line is the number X for the number inputs. The first line of each input is the number Y whereas the second line is Y whole positive numbers that have to be summed. The output should be that sum. Both X and Y are whole and positive numbers.

My C++ code:

#include <iostream>

using namespace std;

int main()
{
    int no_of_inputs;
    int input;
    int table_dim;
    int val;
    int sum = 0;
    cin >> no_of_inputs;
    for (int i = 0; i < no_of_inputs; i++)
    {
        cin >> table_dim;
        for (int i = 0; i < table_dim; i++)
        {
            cin >> val;
            sum += val;
        }
        cout << sum<<endl;

    }
}

Answer 1

You don't reset sum between lines. If you have more than 1 input the later ones will be wrong.

using namespace std; is a terrible habit, kick it.

You are re-declaring i in your inner loop. That doesn't break your program, but it makes it hard to understand.

#include <iostream>

int main()
{
    int no_of_inputs;
    std::cin >> no_of_inputs;
    for (int i = 0; i < no_of_inputs; i++)
    {
        int table_dim;
        std::cin >> table_dim;
        int sum = 0;
        for (int j = 0; j < table_dim; j++)
        {
            int val;
            std::cin >> val;
            sum += val;
        }
        std::cout << sum << std::endl;
    }
}