当int变量大于10位时

Question

When the int variable is more than 10 digits, an error occurs and the number becomes negative.

Why is this happening and how can I solve the problem?

This is my code:

UnityWebRequest www = new UnityWebRequest("https://api.hypixel.net/skyblock/bazaar");
www.downloadHandler = new DownloadHandlerBuffer();
yield return www.SendWebRequest();
JSONNode itemsData = JSON.Parse(www.downloadHandler.text);
unixtimeOnline = itemsData2["lastUpdated"];
Debug.Log(unixtimeOnline);
    // output -2147483648

Answer 1

tl;dr

Simply use ulong instead of int for unixtimeOnline

ulong unixtimeOnline = itemsData2["lastUpdated"];

---

What happened?

As was already mentioned int (or also System.Int32 ) has 32 bits.

The int.MaxValue is

2147483647

no int can be higher than that. What you get is basically a byte overflow .

From the JSON.Parse I suspect you are usingSimpleJson

and if you have

int unixtimeOnline = itemsData2["lastUpdated"];

it will implicitly use

public static implicit operator int(JSONNode d) { return (d == null)? 0: d.AsInt; }

which uses AsInt

 public virtual int AsInt { get { return (int)AsDouble; } set { AsDouble = value; } }

which is a problem because a double can hold up to

so when you simply do

double d = 2147483648.0;
int example = (int)d;

you will again get

-2147483648

---

What you want

You want to use a type that supports larger numbers. Like eg

• long : goes up to

  9,223,372,036,854,775,807

  and is actually what system time ticks are usually stored as (see eg DateTime.Ticks

or actually since your time is probably never negative anyway directly use the unsigned ones

• ulong : goes up to

  18,446,744,073,709,551,615

---

Solution

Long store short: There are implicit conversion for the other numeric values so all you need to do is use

ulong unixtimeOnline = itemsData2["lastUpdated"];

and it will use AsUlong instead

 public static implicit operator ulong(JSONNode d) { return (d == null)? 0: d.AsULong; }

which now correctly uses

 public virtual ulong AsULong { get { ulong val = 0; if (ulong.TryParse(Value, out val)) return val; return 0; } set { Value = value.ToString(); } }

Answer 2

As the comment says you will need to use a long variable type