Given a sequence of integers as input I need to be able to select specific integers of the sequence so that I can execute various arithmetic operations between them.
For example, given this input I want to know the sum of the third and the last integer of the sequence.
EDIT: in the example it would be the sum of 7 and 9
3
1
7
4
9
The condition I have to follow is that I don't use arrays so I can't give every integer an index.
Also I can't know in advance how many integers there will be in the sequence so I can't create an input that determine the number of integers.
To read the inputs I thought of using this loop with a scanf condition:
while (scanf("%d", &i) == 1);
The thing I'm stuck in is how to select the third and the last integers; if it was something like finding the sum of the odd integers I would just put a condition like this:
if (i%2 != 0)
{
sum = sum + i;
i++;
}
Most examples are solved using a for lopp but they either have the number of inputs declared or the inputs are just consecutive integers.
Any suggestion on how can I solve this problem?