Why we are writing int sum=0; and sum+=arr[x]; there

Question

#include <iostream>
using namespace std;

int main()
{
int arr[] = {11, 35, 62, 555, 989};
int sum = 0;

for (int x = 0; x < 5; x++) {
sum += arr[x];
}

cout << sum << endl;

return 0;
}

Answer 1

This program is calculating sum of numbers present in array.
int sum=0;
Here, You are declaring variable sum and initializing it by 0 so that there is no garbage value.
The variable sum will store the sum of numbers present in the array.
sum+=arr[x];
It is same as writing:
sum=sum+arr[x];
Here, You are calculating sum of numbers present in array.
x is used to access the values stored in array arr[].

Answer 2

Got it thx