Output of C++ code

Question

Can someone explain this C++ code?
https://code.sololearn.com/cdRICRoQ28tU/#cpp

Answer 1

That's a special for loop used for arrays..(edit : vector, map,... A collection of iterable types)
Syntax is
for( type variable : array)
{
...
}
Variable is assigned array value in sequence from index 0 to length-1 in each next iterations.. Like a normal for loop.

But in first loop,
int i = a; is normal assignment a also variable.
But int &i =a ; is assigning address of a in address of i so now I and a will point to same locations so change in one variable will change in other variables also... So in first loop change in i will replect back to array value. So that's why array values also changing..

Edit : Arsenic
I specified relating to code specific only.. (In that code)
Ok. C++ has vectors and map also.. So if it misleading, I edit it.

It works for any collection of elements type.. Ex: array, vector..
Done.. 👍

Answer 2

You are using 2 ranged based *for* loops here :-

The first one is traversing the entire array and is reducing the ACTUAL values in it by 1

The second one is just displaying each value of array.

Answer 3

Jayakrishna🇮🇳 it's not specific for arrays. It is a ranged based loop which can be used to iterate over any range of values, for example std::vector , std::map or any other C++ Standard Library sequence whose range is defined by a begin() and end()

Edward Finkelstein have a look at this 👇 to learn more about ranged based *for* loops in C++
https://docs.microsoft.com/en-us/cpp/cpp/range-based-for-statement-cpp

Answer 4

thank you Arsenic!

Answer 5

what do the : and the & symbol do?

Answer 6

thank you Jayakrishna!