When I tried to run the code I was getting the 2nd output as garbage value. Can anyone tell fault in that code

Question

#include <iostream>

using namespace std;

int main()
{
int T,i,j,N,K;
cin >> T;
int n[T],x;
for(i=1; i<=T; i++)
{
    cin >> N >> K;
    for(int j=1; j<=N; j++)
    {
        cin >> x;
        n[i]+=x/K;
        x=0;
    }N=0;K=0;

    }
for(i=1; i<=T; i++)
    cout << n[i] << endl;
return 0;
}

question is "Your program will be tested on one or more test cases.The first line of the input will be a single integer T, the number of test cases (1 ≤ T ≤ 100). Followed by the test cases, each test case is on two lines. The first line of each test case contains two integers N, the number of different candies (1 ≤ N ≤ 100), and K, the minimum number of candies which will make a kid happy as described above (1 ≤ K ≤ 100). The second line of each test case contains N integers, separated by a single space, which are the available number of candies of each type. There will be at least 1 candy and at most 100 candies of each type."

sample input: 2
3 2
4 5 7
3 8
4 5 7
sample output:
7
0

 when the i tried the above code the answer that i got like: 
 input:2
 3 2
 5 6 8
 2 2
 9 1
 output:
 9
 -880625041

When i tried to run the code i was getting the 2nd output as garbage value. Can anyone tell me the fault in that code

Answer 1

1. Arrays in C and C++ are zero-based. Run your loops from 0 to N - 1 and T - 1.

2. You don't initialise your array values before using them. Formally your program behaviour is undefined. (I think you mean n[i]= rather than n[i]+= .)

3. Variable length arrays like int n[T] are compiler extensions. Do bear this in mind as it could affect portability.

Answer 2

Here is the problem:

 n[i]+=x/K;

this is equivalent to n[i]=n[i]+x/K; So it uses a prior value of n[i] . However, you haven't set any prior value to elements of the array n . So, initialise the array to 0 first.

      for(i=0;i<T;i++)
         n[i] = 0;

Also, in this code:

  for(int j=1; j<=N; j++)

are you sure that N will always be less than T , the size of array? (take care of 0-based indexing as well).