A C program question, please help you!

Will you be too old to see clearly? This is the overload of the constructor, which is when I instantiate.

menumodel newmodel=new menumodel();This is an empty object, and what he executes is public menuModel().

This function, if instantiated, is written like this:

menumodel newmodel=new menumodel();

menumodel newmodel2=new menumodel(newmodel);

Then he will execute the protected menumodel (menumodel model).

If there is no custom constructor, the system will automatically generate a default constructor with empty parameters, and if you define your own constructor in the class, the system will not generate an empty constructor, and the programming language requires that it must contain an empty constructor.

If you don't have a default method in this class, and you don't write a new method to this class, then you're going to make an error when instantiating this class, and you're giving you one by default to prevent errors.

It means that it has been added twice, and my understanding is like this:

Clause. 1. When the cycle ends, k is added at the end, so it should be at least k-1;

Clause. Second, because it is the while(bool) loop in the while loop, this loop has a characteristic that it loops first and then judges, which means that it will execute the loop at least once regardless of whether the conditions are met or not, so in the end, s has exceeded 2000 before stopping the loop, so that k adds one more time, and it is another k-1.

To sum up, we can get K-2.

It should indeed be K-2

while (s < 2000) If s is less than 2000, it means that the cycle has been overrun, so here you need to subtract 1 for the first time;

And the purpose of subtracting 1 this time is to turn k into a number before k++.

When s < 2000, in fact, for k at this time, s = s+(k-1)*(k-1);

So when you finally return, you need to put the last K-2;

For example; int s=0,k=1;

while(s<6)

1st round k=1; s=1 when the round ends, k=2, second round, k=2:s=5, when the round ends, k=3, third: k=3; s=14.

At the end of the fourth round, k=4, the end loop k-1 simply returns k to 3 (i.e., the initial value of the third round), but the calculated s of this initial value is equal to 14 and does not satisfy the cycle condition, so it needs to be subtracted by 1

Just write k, that's wrong.

int k = 1, sum = 0;define variables and initialize while (sum < 2000) using while constraints); The maximum k value of the print satisfies the relation.

Let the page stop.

I think it's supposed to be K-1;

How is it K-2?

This equation is equivalent to (n++)n--)n, and the self-increment and self-decrement operations placed after the variable are performed after the value of the expression is calculated.

So, the value of the expression is equal to n+n-n, and the result is equal to n.

After calculating the value of the expression, we can increase and subtract n by adding and subtracting, and the value of n remains unchanged.