Checking the neighbour values of arrays - c++

Question

I have an array of numbers with length L, and I have to make the program check the sums of every array element with its preceding and following neighbors.
So, for example, if I have the array being {1, 2, 3}, the output for the 2nd element should be 6 because 1 + 2 + 3 = 6 and they are all neighbors.
If the chosen element is the first element in the array, its preceding neighbor is the last element of the array, and if the element is the last element in the array, the following neighbor is the first element of the array. So, in the {1, 2, 3} example, no matter what number you check, you always get 6, but if it were {1, 2, 3, 4} instead, the answer for the 3rd element would be 9 because 3 + 2 + 4 = 9.
I hope you understood how it should work.
The problem I am getting is that the output is out of control. I tried to check the array itself and it is completely normal. In the {1, 2, 3} example, I get an output of 7208681 and I don't know why.
#include <iostream>
using namespace std;
int main()
{
int total;
cin >> total;
int Bush[total]; //array of numbers
int temp, output = 0; //output variable and a container for the last resurt a.k.a temp
for (int i = 0; i <= total - 1; i++)
{
cin >> Bush[i]; //inputting the array elements
}
for (int i = 0; i < total; i++)
{
if (i == 0)
output = Bush[i] + Bush[i + 1] + Bush[total]; //checking if the loop checks the first number
if (i == total - 1)
output = Bush[i] + Bush[0] + Bush[i - 1]; //checking if the loop checks the first number
temp = output; //assigning the temp value to the current output value
output = Bush[i] + Bush[i + 1] + Bush[i - 1]; //assigning a new output value
if (temp > output)
output = temp; //checking values
}
cout << output << endl; //outputting
return 0;
}

Answer 1

When i = 0, the expression Bush[i-1] results in accessing an invalid location of the array (- 1).
Similarly, when i = total - 1 (last index of iteration), the expression Bush[i+1] gives you an index of total which is out of bounds of the array.

Answer 2

The last element of Bush is at index total -1, but you are accessing Bush[total] when i==0

Answer 3

At the end, there are many mistakes in your code, nonetheless, the problem with the if/else structure.
I would suggest you to use another inner loop, based on module operator that simplify the code a lot:
int max = 0;
for(int i = 0; i<total; i++)
{
output = Bush[i] + Bush[(i+1)%total] + Bush[(i-1+total)%total];
if(max < output) max = output;//checking the max
}
cout<<max<<endl;//outputting
that does the operation you required.
Hope this may help.

Answer 4

I think the below code would work
int main()
{
int total;
cout << "Enter Number of Elements " << endl;
cin>>total;
int Bush[total];//array of numbers
int temp = 0, output = INT_MIN; //output variable and a container for the last resurt a.k.a temp
cout << "Enter the Elements " << endl;
for(int i = 0; i<=total - 1; i++)
{
cin>>Bush[i];//inputting the array elements
}
for(int i = 0; i<total; i++)
{
if(i == 0)
temp = Bush[i] + Bush[i+1] + Bush[total -1];//checking if the loop checks the first number
else if(i == total - 1)
temp = Bush[i] + Bush[0] + Bush[i-1];//checking if the loop checks the first number
else
temp = Bush[i] + Bush[i+1] + Bush[i-1]; //assigning the temp value to the current output value
output = (temp > output)?temp:output;
}
cout<<output<<endl;//outputting
return 0;
}