How is this operator += works in c++??

Question

while (num <= 5) {
cin >> number;
total += number;
num++;
}

Answer 1

total += number

is

total = total + number

Answer 2

the operator += in this example is the same as writing
total = total + number;
it's just a shortcut, it makes the code look better and respects one of the most fundamental rules when programming. the DRY rule (aka Don't Repeat Yourself).

Answer 3

Here,
total+=number : it is, total = total + number.
it is a shorter way to express it.
and number ++: this add the number by one and again enter the loop and this will carry on until the given statement in the while statement becomes incorrect.

Answer 4

Total= total+number