Java 创建一个随机的 4 位数字，并将其存储为字符串
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Creating a random 4 digit number, and storing it to a string
提问by user3247335
I'm trying to create a method which generates a 4 digit integer and stores it in a string.
The 4 digit integer must lie between 1000 and below 10000. Then the value must be stored to PINString.
Heres what I have so far. I get the error Cannot invoke toString(String) on the primitive type int. How can I fix it?
我正在尝试创建一个生成 4 位整数并将其存储在字符串中的方法。4 位整数必须介于 1000 和 10000 以下。然后该值必须存储到PINString. 这是我到目前为止所拥有的。我收到错误Cannot invoke toString(String) on the primitive type int。我该如何解决？
public void generatePIN()
{
//generate a 4 digit integer 1000 <10000
int randomPIN = (int)(Math.random()*9000)+1000;
//Store integer in a string
randomPIN.toString(PINString);
}
采纳答案by mikejonesguy
You want to use PINString = String.valueOf(randomPIN);
你想用 PINString = String.valueOf(randomPIN);
回答by Alexis C.
randomPINis a primitive datatype.
randomPIN是原始数据类型。
If you want to store the integer value in a String, use String.valueOf:
如果要将整数值存储在 a 中String，请使用String.valueOf：
String pin = String.valueOf(randomPIN);
回答by peter.petrov
Try this approach. The x is just the first digit. It is from 1 to 9.
Then you append it to another number which has at most 3 digits.
试试这个方法。x 只是第一个数字。它是从 1 到 9。
然后将它附加到另一个最多 3 位数的数字上。
public String generatePIN()
{
int x = (int)(Math.random() * 9);
x = x + 1;
String randomPIN = (x + "") + ( ((int)(Math.random()*1000)) + "" );
return randomPIN;
}
回答by Zied R.
Use a string to store the value:
使用字符串存储值：
String PINString= String.valueOf(randomPIN);
回答by Sharp Edge
Make a String variable, concat the generated int value in it:
创建一个 String 变量，将生成的 int 值连接到其中：
int randomPIN = (int)(Math.random()*9000)+1000;
String val = ""+randomPIN;
OR even more simple
或者更简单
String val = ""+((int)(Math.random()*9000)+1000);
Can't get any more simple than this ;)
没有比这更简单的了 ;)
