Why that result: 7

Question

Here is task:
int a[3]={3,2,2};
for (int i=1; i<3; i++){
a[0]+=a[i];
}
cout<<a[0];

Answer 1

a[0] = a[0]+ a[i]
and initially a[0]= 3 so as the for loop starts
initially i=1 so
a[0]=a[0]+a[1] which is 3+2=5
now value of a[0]=5 furthermore value of i increase to 2 condition is still true now
a[0]=a[0]+a[2] which is 5+2=7
and now i=3 and condition becomes false..
end of loop so output=7
Hope it helps...

Answer 2

Let's see:
i = 1; a[0] = 3.
i = 2; a[0] = 3+2=5.
i = 3; a[0] = 5+2=7.
So, the final a[0]=7.

Answer 3

Firstly you declared a[0]=3, a[1]=2, a[2]=2,
Then loop started.
When i=1,
then a[0]=a[0]+a[1];
a[0]=3+2=5; //a[1]=2
When i=2,
a[0]=a[0]+a[2];
So a[0]=5+2=7;//a[2]=2
Then the loop will break;
so when you print a[0] the answer is 7